config.site - R - Git at Google

 #! /bin/sh

 ### This file is part of R.
 ###
 ### R is free software; you can redistribute it and/or modify it under
 ### the terms of the GNU General Public License as published by the Free
 ### Software Foundation; either version 2 of the License, or (at your
 ### option) any later version.
 ###
 ### R is distributed in the hope that it will be useful, but WITHOUT ANY
 ### WARRANTY; without even the implied warranty of MERCHANTABILITY or
 ### FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
 ### License for more details.
 ###
 ### You should have received a copy of the GNU General Public License
 ### along with R; if not, a copy is available at
 ### http://www.r-project.org/Licenses/

 ## By means of this file you can (also) provide default values for the
 ## configuration process.  To set variables, uncomment the VAR=DEFAULT
 ## lines and set DEFAULT according to your needs.
 ## See etc/Renviron.in for further variables you may wish to set.

 ## The command used to spool PostScript files to the printer.
 ## If unspecified, the system will look for either 'lpr' or 'lp'.
 ## R_PRINTCMD=lpr

 ## The paper size for the local (PostScript) printer.
 ## It must either be left blank or set to one of 'a4' or 'letter'.
 ## If left blank the system will use 'a4'.
 ## R_PAPERSIZE=a4

 ## Set the default behavior of R when ending a session
 ## Set this to one of '--save' or '--no-save' depending whether you
 ## want automatic saving of '.RData' or not.
 ## Note that this applies to interactive and batch use,
 ## but NOT to the utility R CMD BATCH
 ## (which defaults to --save irrespective of this setting)
 ## R_BATCHSAVE=

 ## The command which runs the C compiler.
 ## If unspecified, a search is made for gcc and cc (in that order).
 ## To override this choice, specify the name or path of the command
 ## which runs the compiler, for example 'c99'.
 ## It is also necessary to set the architecture here, e.g. 'gcc -m32'.
 ## CC=

 ## Debugging and optimization options for the C compiler.
 ## Use this to specify CFLAGS for the version of the C compiler
 ## specified above.
 ## If unspecified, defaults to '-g -O2' for gcc,
 ## and '-g' in all other cases except icc (for which see R-admin.html).
 ## CFLAGS=

 ## Defines for C compilation.
 ## Use this to specify defines to be used in the compilation of R,
 ## DEFS=

 ## The following additional CFLAGS to be used only in the main
 ## compilation and only in building shared objects respectively.
 ## For example, on some systems one needs 'MAIN_CFLAGS=-pg' when
 ## profiling.
 ## MAIN_CFLAGS=
 ## SHLIB_CFLAGS=

 ## Header file search directory ('-IDIR') and any other miscellaneous
 ## options (such as defines) for the C preprocessor and compiler.
 ## If unset defaults to '-I/usr/local/include', with '-I/sw/include'
 ## prepended on systems using Fink with root '/sw'.
 ## CPPFLAGS=

 ## The command which runs the Fortran compiler.
 ## Used for both fixed-form and free-form Fortran
 ## FC=

 ## Options for the Fortran compiler.
 ## Use this to specify comilation flags for fixed-form Fortran.
 ## FFLAGS=
 ## Ditto for free-form Fortran.
 ## FCFLAGS=
 ## If just one of these is set, it is used for both.
 ## If both are unspecified, defaults to '-g -O2' for gfortran,
 ## otherwise '-g' if this is accepted, otherwise ''.
 ## Use these if the compiler needs flags such as --free, -qfixed and
 ## cannot determine which from the source-file extension.

 ## Additional libraries needed to link a shared object with FC,
 ## e.g. on x86 Solaris
 ## FCLIBS_XTRA=

 ## Options for safe compilation under the Fortran compiler.
 ## Use this to specify FFLAGS for the version of the compiler specified
 ## above, using as accurate a result as possible, e.g. no optimization
 ## or using -ffloat-store.
 ## SAFE_FFLAGS=

 ## The following additional FFLAGS to be used only in the main
 ## compilation and only in building shared objects respectively.
 ## For example, on some systems one needs 'MAIN_FFLAGS=-pg' when
 ## profiling.
 ## MAIN_FFLAGS=
 ## SHLIB_FFLAGS=

 ## The command to be used to load the main R binary.
 ## This is usually the C compiler, but the automatic
 ## choice can be overridden by means of this variable.
 ## MAIN_LD=

 ## The flags which are necessary for loading main program which will
 ## load DLLs at runtime.  HP-UX and Linux-elf are examples of platforms
 ## which use this.  Those platforms are already taken care of by
 ## configure, and anything set here will be in addition unless MAIN_LD
 ## is given.
 ## For example, one can set flags for profiling here.
 ## MAIN_LDFLAGS=

 ## Any special flags which must be used when compiling C code to be
 ## turned into a shared object.  This is typically something like
 ## '-fpic' or '-fPIC'.  If this variable is left unspecified an attempt
 ## is made to automatically detect the correct value.
 ## CPICFLAGS=

 ## The following variable can be used to provide any PIC flags for the
 ## Fortran compiler.  If this variable is left unspecified an
 ## attempt is made to automatically detect the correct value.
 ## FPICFLAGS=

 ## The command to be used to create shared objects which contain object
 ## files from a C or Fortran compiler only.  This is usually the C
 ## compiler or 'ld', but the automatic choice can be overridden by means
 ## of this variable.
 ## SHLIB_LD=

 ## Any special flags which are required by the linker when creating
 ## shared objects containing object files from a C or Fortran
 ## compiler only.  This is usually automatically detected by configure,
 ## and anything set here will be in addition unless SHLIB_LD is given.
 ## SHLIB_LDFLAGS=

 ## ditto for a dynamic library: DYLIB_LDFLAGS defaults to SHLIB_LDFLAGS
 ## DYLIB_LD=
 ## DYLIB_LDFLAGS=

 ## The appropriate 'lib' dir, normally 'lib', but 'lib64' on Linux on
 ## x86_64, mips64, ppc64, sparc64, s390x but not ia64 (except Debian
 ## and derivatives).
 ## LIBnn=

 ## Path ('-L'), and any other miscellaneous options for the linker.
 ## '-L' options set here will be prepended to LD_LIBRARY_PATH (or its
 ## system equivalent) at run time.
 ## If unset defaults to '-L/usr/local/lib', with '-L/sw/lib' prepended
 ## on macOS systems using Fink with root '/sw'.
 ## On some Linux 64-bit systems its default is -L/usr/local/lib64.
 ## If LIBnn is set it defaults to -L/usr/local/$LIBnn.
 ## LDFLAGS=


 ## The command which runs the C++ compiler.
 ## This is optional, for use in packages.
 ## If not specified, configure
 ## uses the values of the environment variables 'CXX' or 'CCC' if set,
 ## and then looks under the names 'c++', 'g++', 'CC' and more OS-specific
 ## names (from autoconf).
 ## CXX=

 ## Options for the C++ compiler.
 ## CXXFLAGS=

 ## Any special flags which must be used when compiling C++ code to be
 ## turned into a shared object.  If this variable is left unspecified
 ## an attempt is made to automatically detect the correct value.
 ## CXXPICFLAGS=

 ## Option to specify the default C++ standard,
 ## e.g. -std=c++11 or -std=gnu++11
 ## CXXSTD=

 ## The command to be used to load shared objects which contain object
 ## files from the C++ compiler.  This is usually the C++ compiler/linker,
 ## but the automatic choice can be overridden by means of this
 ## variable.  (Include $(CXXSTD) if set.)
 ## SHLIB_CXXLD=

 ## Any special flags which are required when creating shared objects
 ## containing object files from a C++ compiler.  This is usually
 ## automatically detected by configure, and anything set here will be in
 ## addition unless SHLIB_CXXLD is given.
 ## SHLIB_CXXLDFLAGS=

 ## Not used by R but configure can fail to find it, so set to
 ## "$CXX -E" if it does.
 ## CXXCPP=

 ## Tcl/Tk settings.
 ## Use TCLTK_LIBS for all '-L' and '-l' options needed for linking
 ## against the Tcl and Tk library.
 ## TCLTK_LIBS=
 ## Use TCLTK_CPPFLAGS for all '-I' options needed for finding the tcl.h
 ## and tk.h headers.
 ## TCLTK_CPPFLAGS=

 ## Browser default
 ## Default setting for the R_BROWSER env variable
 ## If unset configure searches in turn for (currently)
 ## firefox mozilla galeon opera xdg-open kfmclient gnome-moz-remote open
 ## and uses the full path of the first it finds.
 ## R_BROWSER=

 ## BLAS and LAPACK settings
 ## Use BLAS_LIBS for all '-L' and '-l' options needed for linking
 ## against an external BLAS implementation.
 ## BLAS_LIBS=
 ## Use LAPACK_LIBS for all '-L' and '-l' options needed for linking
 ## against an external LAPACK implementation.
 ## Note that (see R-admin) that our main intention is to allow a
 ## LAPACK-containing BLAS to be used, so this is rarely needed, and
 ## it is not used if the BLAS already contains LAPACK.
 ## LAPACK_LIBS=

 ## Make name or path
 ## Set this if you want to use a make by another name.
 ## For example, if your GNU make is called 'gmake', use 'MAKE=gmake'.
 ## MAKE=

 ## Tar name or path
 ## Set this to prefer a tar which has the capability to automagically
 ## read compressed archives.  The default is to choose 'gtar' or
 ## 'gnutar'(normally GNU tar) then 'tar'.
 ## Note that 'bsdtar' (from the libarchive project) is known to create
 ## archives in a non-POSIX format that other tars and untar() cannot
 ## read, so should be avoided.
 ## TAR=

 ## Dynamic library path
 ## This is be default created from libraries added to LIBS.
 ## Used for DYLD_FALLBACK_LIBRARY_PATH on macOS and LD_LIBRARY_PATH elsewhere.
 ## Allow user to override.
 ## R_LD_LIBRARY_PATH=

 ## C++98 compiler, optional for use in packages.
 ## Introduced in R 3.4.0
 ## The command which runs the C++98 compiler: defaults to $(CXX), but
 ## empty if that (plus standard) cannot compile the tested C++98 code.
 ## CXX98=

 ## The 'standard' for the C++98 compiler, which is invoked as
 ## $(CXX98) $(CXX98STD) for both compiling and linking DSOs/DLLs.
 ## '-std=gnu++98' and '-std=gnu++03' are tried in turn by configure.
 ## followed by '-std=c++98' and '-std=c++03'
 ## CXX98STD=

 ## Analogues for the C++98 compiler: default to the settings for C++
 ## CXX98FLAGS=
 ## CXX98PICFLAGS=
 ## SHLIB_CXX98LD=
 ## SHLIB_CXX98LDFLAGS=

 ## C++11 compiler, optional for use in packages.
 ## Introduced in R 3.1.0
 ## The command which runs the C++11 compiler: defaults to $(CXX), but
 ## empty if that (plus standard) cannot compile the tested C++11 code.
 ## CXX11=

 ## The 'standard' for the C++11 compiler, which is invoked as
 ## $(CXX11) $(CXX11STD) for both compiling and linking DSOs/DLLs.
 ## '-std=gnu++11' and '-std=gnu++0x' are tried in turn by configure.
 ## followed by '-std=c++11' and '-std=c++0x'
 ## CXX11STD=

 ## Analogues for the C++11 compiler: default to the settings for C++
 ## CXX11FLAGS=
 ## CXX11PICFLAGS=
 ## SHLIB_CXX11LD=
 ## SHLIB_CXX11LDFLAGS=

 ## C++14 compiler, optional for use in packages.
 ## Introduced in R 3.4.0
 ## The command which runs the C++14 compiler: defaults to $(CXX11), but
 ## empty if that (plus standard) cannot compile the tested C++14 code.
 ## CXX14=

 ## The 'standard' for the C++14 compiler, which is invoked as
 ## $(CXX14) $(CXX14STD) for both compiling and linking DSOs/DLLs.
 ## '-std=gnu++14' and '-std=gnu++1y" are tried by configure, also
 ## '-std=c++14' and '-std=c++1y"
 ## CXX14STD=

 ## Analogues for the C++14 compiler: default to the settings for C++11
 ## CXX14FLAGS=
 ## CXX14PICFLAGS=
 ## SHLIB_CXX14LD=
 ## SHLIB_CXX14LDFLAGS=

 ## C++17 compiler, optional for use in packages.
 ## Introduced in R 3.4.0
 ## The command which runs the C++17 compiler: defaults to $(CXX14), but
 ## empty if that (plus standard) cannot compile the tested C++17 code.
 ## CXX17=

 ## The 'standard' for the C++17 compiler, which is invoked as
 ## $(CXX17) $(CXX17STD) for both compiling and linking DSOs/DLLs.
 ## '-std=gnu++17' and '-std=gnu++1z" are tried by configure, also
 ## '-std=c++17' and '-std=c++1z"
 ## CXX17STD=

 ## Analogues for the C++17 compiler: default to the settings for C++14
 ## CXX17FLAGS=
 ## CXX17PICFLAGS=
 ## SHLIB_CXX17LD=
 ## SHLIB_CXX17LDFLAGS=

 ## Additional libraries to link the internet module against.
 ## Some claim Solaris needs -lsocket -lnsl
 ## INTERNET_LIBS=

 ## Script from texinfo 5.1 or later.
 ## Usually the full path to texi2any.
 ## TEXI2ANY=

 ## Full path to version of curl-config to be used
 ## CURL_CONFIG=
 ## Use these to override curl-config if needed.
 ## Used as from R 3.2.0.
 ## CURL_CPPFLAGS=
 ## CURL_LIBS=
 ## To force a static link use the line below: this is only needed
 ## if both shared and static libcurl libraries were built.
 ## CURL_LIBS=`curl-config --static-libs`

 ## Path to the version of pkg-config to be used for locating cairographics,
 ## and possibly jpeg, libpng and libtiff.
 ## PKG_CONFIG=
 ## search path for pkg-config
 ## PKG_CONFIG_PATH=
 ## path overriding pkg-config's default search path
 ## PKG_CONFIG_LIBDIR=

 ## OpenMP settings.
 ## The configure code is conservative about enabling OpenMP
 ## so use can be forced here (or non-use if set but empty).
 ## For packages (note that SHLIB_OPENMP_CXXFLAGS is for CXX, not
 ## necessarily for CXX11/14/17).
 ## SHLIB_OPENMP_CFLAGS=
 ## SHLIB_OPENMP_CXXFLAGS=
 ## SHLIB_OPENMP_FFLAGS=
 ## For R itself (src/main/array.c and src/library/stats/src/distance.c)
 ## R_OPENMP_CFLAGS=

 ## POSIX threads setting
 ## pthreads is used in src/main/eval.c.  The configure code sees if
 ## any flag is needed to link to pthread functions (after the OpenMP
 ## CFLAGS) and if so tries -pthread.  Setting this allows an
 ## alternative to be tried immediately before -pthread.
 ## PTHREAD_OPT=

 ## Visibility settings
 ## Allow user to override the configure checks if they know what they
 ## are doing.
 ## C_VISIBILITY=
 ## CXX_VISIBILITY=
 ## F_VISIBILITY=

 ## Fortran-C compatibility
 ## The C type used by Fortran to pass 'hidden' character lengths (if any)
 ## Often size_t (unsigned int or long, or long long in Win64)
 ## Allow user to override the configure checks if they know what they
 ## are doing (the value is unchecked).
 ## FC_LEN_T=

 ## C Stack Direction
 ## In case optimization defeats the configure test: 'down' (the usual) or 'up'
 ## R_C_STACK_DIRECTION=
	#! /bin/sh

	### This file is part of R.
	###
	### R is free software; you can redistribute it and/or modify it under
	### the terms of the GNU General Public License as published by the Free
	### Software Foundation; either version 2 of the License, or (at your
	### option) any later version.
	###
	### R is distributed in the hope that it will be useful, but WITHOUT ANY
	### WARRANTY; without even the implied warranty of MERCHANTABILITY or
	### FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
	### License for more details.
	###
	### You should have received a copy of the GNU General Public License
	### along with R; if not, a copy is available at
	### http://www.r-project.org/Licenses/

	## By means of this file you can (also) provide default values for the
	## configuration process. To set variables, uncomment the VAR=DEFAULT
	## lines and set DEFAULT according to your needs.
	## See etc/Renviron.in for further variables you may wish to set.

	## The command used to spool PostScript files to the printer.
	## If unspecified, the system will look for either 'lpr' or 'lp'.
	## R_PRINTCMD=lpr

	## The paper size for the local (PostScript) printer.
	## It must either be left blank or set to one of 'a4' or 'letter'.
	## If left blank the system will use 'a4'.
	## R_PAPERSIZE=a4

	## Set the default behavior of R when ending a session
	## Set this to one of '--save' or '--no-save' depending whether you
	## want automatic saving of '.RData' or not.
	## Note that this applies to interactive and batch use,
	## but NOT to the utility R CMD BATCH
	## (which defaults to --save irrespective of this setting)
	## R_BATCHSAVE=

	## The command which runs the C compiler.
	## If unspecified, a search is made for gcc and cc (in that order).
	## To override this choice, specify the name or path of the command
	## which runs the compiler, for example 'c99'.
	## It is also necessary to set the architecture here, e.g. 'gcc -m32'.
	## CC=

	## Debugging and optimization options for the C compiler.
	## Use this to specify CFLAGS for the version of the C compiler
	## specified above.
	## If unspecified, defaults to '-g -O2' for gcc,
	## and '-g' in all other cases except icc (for which see R-admin.html).
	## CFLAGS=

	## Defines for C compilation.
	## Use this to specify defines to be used in the compilation of R,
	## DEFS=

	## The following additional CFLAGS to be used only in the main
	## compilation and only in building shared objects respectively.
	## For example, on some systems one needs 'MAIN_CFLAGS=-pg' when
	## profiling.
	## MAIN_CFLAGS=
	## SHLIB_CFLAGS=

	## Header file search directory ('-IDIR') and any other miscellaneous
	## options (such as defines) for the C preprocessor and compiler.
	## If unset defaults to '-I/usr/local/include', with '-I/sw/include'
	## prepended on systems using Fink with root '/sw'.
	## CPPFLAGS=

	## The command which runs the Fortran compiler.
	## Used for both fixed-form and free-form Fortran
	## FC=

	## Options for the Fortran compiler.
	## Use this to specify comilation flags for fixed-form Fortran.
	## FFLAGS=
	## Ditto for free-form Fortran.
	## FCFLAGS=
	## If just one of these is set, it is used for both.
	## If both are unspecified, defaults to '-g -O2' for gfortran,
	## otherwise '-g' if this is accepted, otherwise ''.
	## Use these if the compiler needs flags such as --free, -qfixed and
	## cannot determine which from the source-file extension.

	## Additional libraries needed to link a shared object with FC,
	## e.g. on x86 Solaris
	## FCLIBS_XTRA=

	## Options for safe compilation under the Fortran compiler.
	## Use this to specify FFLAGS for the version of the compiler specified
	## above, using as accurate a result as possible, e.g. no optimization
	## or using -ffloat-store.
	## SAFE_FFLAGS=

	## The following additional FFLAGS to be used only in the main
	## compilation and only in building shared objects respectively.
	## For example, on some systems one needs 'MAIN_FFLAGS=-pg' when
	## profiling.
	## MAIN_FFLAGS=
	## SHLIB_FFLAGS=

	## The command to be used to load the main R binary.
	## This is usually the C compiler, but the automatic
	## choice can be overridden by means of this variable.
	## MAIN_LD=

	## The flags which are necessary for loading main program which will
	## load DLLs at runtime. HP-UX and Linux-elf are examples of platforms
	## which use this. Those platforms are already taken care of by
	## configure, and anything set here will be in addition unless MAIN_LD
	## is given.
	## For example, one can set flags for profiling here.
	## MAIN_LDFLAGS=

	## Any special flags which must be used when compiling C code to be
	## turned into a shared object. This is typically something like
	## '-fpic' or '-fPIC'. If this variable is left unspecified an attempt
	## is made to automatically detect the correct value.
	## CPICFLAGS=

	## The following variable can be used to provide any PIC flags for the
	## Fortran compiler. If this variable is left unspecified an
	## attempt is made to automatically detect the correct value.
	## FPICFLAGS=

	## The command to be used to create shared objects which contain object
	## files from a C or Fortran compiler only. This is usually the C
	## compiler or 'ld', but the automatic choice can be overridden by means
	## of this variable.
	## SHLIB_LD=

	## Any special flags which are required by the linker when creating
	## shared objects containing object files from a C or Fortran
	## compiler only. This is usually automatically detected by configure,
	## and anything set here will be in addition unless SHLIB_LD is given.
	## SHLIB_LDFLAGS=

	## ditto for a dynamic library: DYLIB_LDFLAGS defaults to SHLIB_LDFLAGS
	## DYLIB_LD=
	## DYLIB_LDFLAGS=

	## The appropriate 'lib' dir, normally 'lib', but 'lib64' on Linux on
	## x86_64, mips64, ppc64, sparc64, s390x but not ia64 (except Debian
	## and derivatives).
	## LIBnn=

	## Path ('-L'), and any other miscellaneous options for the linker.
	## '-L' options set here will be prepended to LD_LIBRARY_PATH (or its
	## system equivalent) at run time.
	## If unset defaults to '-L/usr/local/lib', with '-L/sw/lib' prepended
	## on macOS systems using Fink with root '/sw'.
	## On some Linux 64-bit systems its default is -L/usr/local/lib64.
	## If LIBnn is set it defaults to -L/usr/local/$LIBnn.
	## LDFLAGS=


	## The command which runs the C++ compiler.
	## This is optional, for use in packages.
	## If not specified, configure
	## uses the values of the environment variables 'CXX' or 'CCC' if set,
	## and then looks under the names 'c++', 'g++', 'CC' and more OS-specific
	## names (from autoconf).
	## CXX=

	## Options for the C++ compiler.
	## CXXFLAGS=

	## Any special flags which must be used when compiling C++ code to be
	## turned into a shared object. If this variable is left unspecified
	## an attempt is made to automatically detect the correct value.
	## CXXPICFLAGS=

	## Option to specify the default C++ standard,
	## e.g. -std=c++11 or -std=gnu++11
	## CXXSTD=

	## The command to be used to load shared objects which contain object
	## files from the C++ compiler. This is usually the C++ compiler/linker,
	## but the automatic choice can be overridden by means of this
	## variable. (Include $(CXXSTD) if set.)
	## SHLIB_CXXLD=

	## Any special flags which are required when creating shared objects
	## containing object files from a C++ compiler. This is usually
	## automatically detected by configure, and anything set here will be in
	## addition unless SHLIB_CXXLD is given.
	## SHLIB_CXXLDFLAGS=

	## Not used by R but configure can fail to find it, so set to
	## "$CXX -E" if it does.
	## CXXCPP=

	## Tcl/Tk settings.
	## Use TCLTK_LIBS for all '-L' and '-l' options needed for linking
	## against the Tcl and Tk library.
	## TCLTK_LIBS=
	## Use TCLTK_CPPFLAGS for all '-I' options needed for finding the tcl.h
	## and tk.h headers.
	## TCLTK_CPPFLAGS=

	## Browser default
	## Default setting for the R_BROWSER env variable
	## If unset configure searches in turn for (currently)
	## firefox mozilla galeon opera xdg-open kfmclient gnome-moz-remote open
	## and uses the full path of the first it finds.
	## R_BROWSER=

	## BLAS and LAPACK settings
	## Use BLAS_LIBS for all '-L' and '-l' options needed for linking
	## against an external BLAS implementation.
	## BLAS_LIBS=
	## Use LAPACK_LIBS for all '-L' and '-l' options needed for linking
	## against an external LAPACK implementation.
	## Note that (see R-admin) that our main intention is to allow a
	## LAPACK-containing BLAS to be used, so this is rarely needed, and
	## it is not used if the BLAS already contains LAPACK.
	## LAPACK_LIBS=

	## Make name or path
	## Set this if you want to use a make by another name.
	## For example, if your GNU make is called 'gmake', use 'MAKE=gmake'.
	## MAKE=

	## Tar name or path
	## Set this to prefer a tar which has the capability to automagically
	## read compressed archives. The default is to choose 'gtar' or
	## 'gnutar'(normally GNU tar) then 'tar'.
	## Note that 'bsdtar' (from the libarchive project) is known to create
	## archives in a non-POSIX format that other tars and untar() cannot
	## read, so should be avoided.
	## TAR=

	## Dynamic library path
	## This is be default created from libraries added to LIBS.
	## Used for DYLD_FALLBACK_LIBRARY_PATH on macOS and LD_LIBRARY_PATH elsewhere.
	## Allow user to override.
	## R_LD_LIBRARY_PATH=

	## C++98 compiler, optional for use in packages.
	## Introduced in R 3.4.0
	## The command which runs the C++98 compiler: defaults to $(CXX), but
	## empty if that (plus standard) cannot compile the tested C++98 code.
	## CXX98=

	## The 'standard' for the C++98 compiler, which is invoked as
	## $(CXX98) $(CXX98STD) for both compiling and linking DSOs/DLLs.
	## '-std=gnu++98' and '-std=gnu++03' are tried in turn by configure.
	## followed by '-std=c++98' and '-std=c++03'
	## CXX98STD=

	## Analogues for the C++98 compiler: default to the settings for C++
	## CXX98FLAGS=
	## CXX98PICFLAGS=
	## SHLIB_CXX98LD=
	## SHLIB_CXX98LDFLAGS=

	## C++11 compiler, optional for use in packages.
	## Introduced in R 3.1.0
	## The command which runs the C++11 compiler: defaults to $(CXX), but
	## empty if that (plus standard) cannot compile the tested C++11 code.
	## CXX11=

	## The 'standard' for the C++11 compiler, which is invoked as
	## $(CXX11) $(CXX11STD) for both compiling and linking DSOs/DLLs.
	## '-std=gnu++11' and '-std=gnu++0x' are tried in turn by configure.
	## followed by '-std=c++11' and '-std=c++0x'
	## CXX11STD=

	## Analogues for the C++11 compiler: default to the settings for C++
	## CXX11FLAGS=
	## CXX11PICFLAGS=
	## SHLIB_CXX11LD=
	## SHLIB_CXX11LDFLAGS=

	## C++14 compiler, optional for use in packages.
	## Introduced in R 3.4.0
	## The command which runs the C++14 compiler: defaults to $(CXX11), but
	## empty if that (plus standard) cannot compile the tested C++14 code.
	## CXX14=

	## The 'standard' for the C++14 compiler, which is invoked as
	## $(CXX14) $(CXX14STD) for both compiling and linking DSOs/DLLs.
	## '-std=gnu++14' and '-std=gnu++1y" are tried by configure, also
	## '-std=c++14' and '-std=c++1y"
	## CXX14STD=

	## Analogues for the C++14 compiler: default to the settings for C++11
	## CXX14FLAGS=
	## CXX14PICFLAGS=
	## SHLIB_CXX14LD=
	## SHLIB_CXX14LDFLAGS=

	## C++17 compiler, optional for use in packages.
	## Introduced in R 3.4.0
	## The command which runs the C++17 compiler: defaults to $(CXX14), but
	## empty if that (plus standard) cannot compile the tested C++17 code.
	## CXX17=

	## The 'standard' for the C++17 compiler, which is invoked as
	## $(CXX17) $(CXX17STD) for both compiling and linking DSOs/DLLs.
	## '-std=gnu++17' and '-std=gnu++1z" are tried by configure, also
	## '-std=c++17' and '-std=c++1z"
	## CXX17STD=

	## Analogues for the C++17 compiler: default to the settings for C++14
	## CXX17FLAGS=
	## CXX17PICFLAGS=
	## SHLIB_CXX17LD=
	## SHLIB_CXX17LDFLAGS=

	## Additional libraries to link the internet module against.
	## Some claim Solaris needs -lsocket -lnsl
	## INTERNET_LIBS=

	## Script from texinfo 5.1 or later.
	## Usually the full path to texi2any.
	## TEXI2ANY=

	## Full path to version of curl-config to be used
	## CURL_CONFIG=
	## Use these to override curl-config if needed.
	## Used as from R 3.2.0.
	## CURL_CPPFLAGS=
	## CURL_LIBS=
	## To force a static link use the line below: this is only needed
	## if both shared and static libcurl libraries were built.
	## CURL_LIBS=`curl-config --static-libs`

	## Path to the version of pkg-config to be used for locating cairographics,
	## and possibly jpeg, libpng and libtiff.
	## PKG_CONFIG=
	## search path for pkg-config
	## PKG_CONFIG_PATH=
	## path overriding pkg-config's default search path
	## PKG_CONFIG_LIBDIR=

	## OpenMP settings.
	## The configure code is conservative about enabling OpenMP
	## so use can be forced here (or non-use if set but empty).
	## For packages (note that SHLIB_OPENMP_CXXFLAGS is for CXX, not
	## necessarily for CXX11/14/17).
	## SHLIB_OPENMP_CFLAGS=
	## SHLIB_OPENMP_CXXFLAGS=
	## SHLIB_OPENMP_FFLAGS=
	## For R itself (src/main/array.c and src/library/stats/src/distance.c)
	## R_OPENMP_CFLAGS=

	## POSIX threads setting
	## pthreads is used in src/main/eval.c. The configure code sees if
	## any flag is needed to link to pthread functions (after the OpenMP
	## CFLAGS) and if so tries -pthread. Setting this allows an
	## alternative to be tried immediately before -pthread.
	## PTHREAD_OPT=

	## Visibility settings
	## Allow user to override the configure checks if they know what they
	## are doing.
	## C_VISIBILITY=
	## CXX_VISIBILITY=
	## F_VISIBILITY=

	## Fortran-C compatibility
	## The C type used by Fortran to pass 'hidden' character lengths (if any)
	## Often size_t (unsigned int or long, or long long in Win64)
	## Allow user to override the configure checks if they know what they
	## are doing (the value is unchecked).
	## FC_LEN_T=

	## C Stack Direction
	## In case optimization defeats the configure test: 'down' (the usual) or 'up'
	## R_C_STACK_DIRECTION=