google3/third_party/grte/v5_src/glibc-2.27/sysdeps/unix/inet/configure.ac - GRTEv5 - Git at Google

 dnl glibc configure fragment for sysdeps/unix/inet.
 GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.

 AS_IF([test "$shared" = yes], [
   # Get this defined in config.h for main source code to test.
   AC_DEFINE([HAVE_LIBIDN])
 ])
	dnl glibc configure fragment for sysdeps/unix/inet.
	GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.

	AS_IF([test "$shared" = yes], [
	# Get this defined in config.h for main source code to test.
	AC_DEFINE([HAVE_LIBIDN])
	])