diff -urN eccodes-2.19.1-Source-orig/cmake/ecbuild_add_large_file_support.cmake eccodes-2.19.1-Source/cmake/ecbuild_add_large_file_support.cmake
--- eccodes-2.19.1-Source-orig/cmake/ecbuild_add_large_file_support.cmake	2020-11-02 12:08:23.000000000 +0100
+++ eccodes-2.19.1-Source/cmake/ecbuild_add_large_file_support.cmake	2021-01-12 12:44:46.718252300 +0100
@@ -17,7 +17,7 @@
 
   if( EC_SIZEOF_OFF_T LESS "8" )
 
-    if( ${CMAKE_SYSTEM_NAME} MATCHES "Linux" OR ${CMAKE_SYSTEM_NAME} MATCHES "Darwin" )
+    if( ${CMAKE_SYSTEM_NAME} MATCHES "Linux" OR ${CMAKE_SYSTEM_NAME} MATCHES "Darwin" OR MINGW)
       add_definitions( -D_FILE_OFFSET_BITS=64 )
     elseif( ${CMAKE_SYSTEM_NAME} MATCHES "AIX" )
       add_definitions( -D_LARGE_FILES=64 )
diff -urN eccodes-2.19.1-Source-orig/cmake/ecbuild_bundle.cmake eccodes-2.19.1-Source/cmake/ecbuild_bundle.cmake
--- eccodes-2.19.1-Source-orig/cmake/ecbuild_bundle.cmake	2020-11-02 12:08:23.000000000 +0100
+++ eccodes-2.19.1-Source/cmake/ecbuild_bundle.cmake	2021-01-11 23:29:52.421765400 +0100
@@ -159,7 +159,7 @@
       if( DEFINED ${PNAME}_SOURCE )
         ecbuild_critical( "ecbuild_bundle called with SOURCE for project ${_PAR_PROJECT} but ${PNAME}_SOURCE is defined" )
       endif()
-      execute_process( COMMAND ${CMAKE_COMMAND} -E create_symlink ${_PAR_SOURCE} ${PROJECT_SOURCE_DIR}/${_PAR_PROJECT} )
+      execute_process( COMMAND ${CMAKE_COMMAND} -E copy ${_PAR_SOURCE} ${PROJECT_SOURCE_DIR}/${_PAR_PROJECT} )
     endif()
 
     if( NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${_PAR_PROJECT} OR NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${_PAR_PROJECT}/CMakeLists.txt )
diff -urN eccodes-2.19.1-Source-orig/cmake/ecbuild_declare_project.cmake eccodes-2.19.1-Source/cmake/ecbuild_declare_project.cmake
--- eccodes-2.19.1-Source-orig/cmake/ecbuild_declare_project.cmake	2020-11-02 12:08:23.000000000 +0100
+++ eccodes-2.19.1-Source/cmake/ecbuild_declare_project.cmake	2021-01-11 23:30:11.597396900 +0100
@@ -194,7 +194,7 @@
 
   # make sure nothing breaks if INSTALL_LIB_DIR is not lib
   if( NOT INSTALL_LIB_DIR STREQUAL "lib" AND NOT EXISTS ${CMAKE_BINARY_DIR}/${INSTALL_LIB_DIR} )
-    execute_process( COMMAND ${CMAKE_COMMAND} -E create_symlink lib ${CMAKE_BINARY_DIR}/${INSTALL_LIB_DIR} )
+    execute_process( COMMAND ${CMAKE_COMMAND} -E copy lib ${CMAKE_BINARY_DIR}/${INSTALL_LIB_DIR} )
   endif()
 
   # ecbuild_debug_var( CMAKE_INSTALL_RPATH )
diff -urN eccodes-2.19.1-Source-orig/CMakeLists.txt eccodes-2.19.1-Source/CMakeLists.txt
--- eccodes-2.19.1-Source-orig/CMakeLists.txt	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/CMakeLists.txt	2021-01-12 13:42:58.548836400 +0100
@@ -309,6 +309,7 @@
     set( CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE )
     set( ECCODES_ON_WINDOWS 1 )
 
+    if ( NOT MINGW )
     # Suppress compliler warnings - see ECC-850
     # Suppress warnings about using 'insecure' functions. Fixing this would require changes all over
     # the codebase which would damage portability.
@@ -317,6 +318,7 @@
     ecbuild_add_c_flags("/D_CRT_NONSTDC_NO_DEPRECATE")
     # Suppress C4267: warns about possible loss of data when converting 'size_t' to 'int'.
     ecbuild_add_c_flags("/wd4267")
+    endif()
 endif()
 
 ###############################################################################
@@ -350,7 +352,7 @@
 
 add_definitions( -DHAVE_ECCODES_CONFIG_H )
 
-if( CMAKE_COMPILER_IS_GNUCC )
+if( CMAKE_COMPILER_IS_GNUCC AND NOT MINGW )
     ecbuild_add_c_flags("-pedantic")
 endif()
 
diff -urN eccodes-2.19.1-Source-orig/definitions/CMakeLists.txt eccodes-2.19.1-Source/definitions/CMakeLists.txt
--- eccodes-2.19.1-Source-orig/definitions/CMakeLists.txt	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/definitions/CMakeLists.txt	2021-01-12 13:50:10.188344300 +0100
@@ -45,7 +45,7 @@
 # link to the definitions. See GRIB-786
 file( MAKE_DIRECTORY ${CMAKE_BINARY_DIR}/${INSTALL_DATA_DIR} )
 if( NOT EXISTS "${CMAKE_BINARY_DIR}/${ECCODES_DEFINITION_SUFF}" )
-  execute_process( COMMAND "${CMAKE_COMMAND}" "-E" "create_symlink"
+  execute_process( COMMAND "${CMAKE_COMMAND}" "-E" "copy"
     "${CMAKE_CURRENT_SOURCE_DIR}"
     "${CMAKE_BINARY_DIR}/${ECCODES_DEFINITION_SUFF}" )
 endif()
diff -urN eccodes-2.19.1-Source-orig/eccodes_config.h.in eccodes-2.19.1-Source/eccodes_config.h.in
--- eccodes-2.19.1-Source-orig/eccodes_config.h.in	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/eccodes_config.h.in	2021-01-12 13:05:30.548720700 +0100
@@ -111,6 +111,8 @@
 
 #cmakedefine HAVE_MEMFS
 
+#cmakedefine ECCODES_ON_WINDOWS
+
 #ifdef HAVE_MEMFS
 #undef ECCODES_DEFINITION_PATH
 #define ECCODES_DEFINITION_PATH "/MEMFS/definitions"
diff -urN eccodes-2.19.1-Source-orig/ifs_samples/CMakeLists.txt eccodes-2.19.1-Source/ifs_samples/CMakeLists.txt
--- eccodes-2.19.1-Source-orig/ifs_samples/CMakeLists.txt	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/ifs_samples/CMakeLists.txt	2021-01-11 23:33:10.952510700 +0100
@@ -14,7 +14,7 @@
   execute_process( COMMAND ${CMAKE_COMMAND} -E make_directory ${destination_build} )
   foreach( _file ${_samples} )
     get_filename_component(_filename ${_file} NAME)
-    execute_process( COMMAND ${CMAKE_COMMAND} -E create_symlink
+    execute_process( COMMAND ${CMAKE_COMMAND} -E copy
        ${_file} ${destination_build}/${_filename} )
   endforeach()
 endfunction()
diff -urN eccodes-2.19.1-Source-orig/samples/CMakeLists.txt eccodes-2.19.1-Source/samples/CMakeLists.txt
--- eccodes-2.19.1-Source-orig/samples/CMakeLists.txt	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/samples/CMakeLists.txt	2021-01-11 23:33:26.731000300 +0100
@@ -16,7 +16,7 @@
 # link to the samples in the build directory. See GRIB-786
 file( MAKE_DIRECTORY ${CMAKE_BINARY_DIR}/${INSTALL_DATA_DIR} )
 if( NOT EXISTS "${CMAKE_BINARY_DIR}/${ECCODES_SAMPLES_SUFF}" )
-  execute_process( COMMAND "${CMAKE_COMMAND}" "-E" "create_symlink"
+  execute_process( COMMAND "${CMAKE_COMMAND}" "-E" "copy"
     "${CMAKE_CURRENT_SOURCE_DIR}"
     "${CMAKE_BINARY_DIR}/${ECCODES_SAMPLES_SUFF}" )
 endif()
diff -urN eccodes-2.19.1-Source-orig/src/grib_accessor_class_data_g1second_order_general_extended_packing.c eccodes-2.19.1-Source/src/grib_accessor_class_data_g1second_order_general_extended_packing.c
--- eccodes-2.19.1-Source-orig/src/grib_accessor_class_data_g1second_order_general_extended_packing.c	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/src/grib_accessor_class_data_g1second_order_general_extended_packing.c	2021-01-12 12:51:50.171483600 +0100
@@ -205,7 +205,7 @@
 #define MAX_NUMBER_OF_GROUPS 65534
 #define EFDEBUG 0
 
-static const unsigned long nbits[64] = {
+static const unsigned long long nbits[64] = {
     0x1, 0x2, 0x4, 0x8,
     0x10, 0x20, 0x40, 0x80,
     0x100, 0x200, 0x400, 0x800,
@@ -226,7 +226,7 @@
 
 static long number_of_bits(grib_handle* h, unsigned long x)
 {
-    const unsigned long* n = nbits;
+    const unsigned long long* n = nbits;
     const int count        = sizeof(nbits) / sizeof(nbits[0]);
     long i                 = 0;
     while (x >= *n) {
diff -urN eccodes-2.19.1-Source-orig/src/grib_accessor_class_second_order_bits_per_value.c eccodes-2.19.1-Source/src/grib_accessor_class_second_order_bits_per_value.c
--- eccodes-2.19.1-Source-orig/src/grib_accessor_class_second_order_bits_per_value.c	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/src/grib_accessor_class_second_order_bits_per_value.c	2021-01-12 12:51:41.865058600 +0100
@@ -151,7 +151,7 @@
         0x40000000, 0x80000000
 };
 */
-static const unsigned long nbits[64] = {
+static const unsigned long long nbits[64] = {
     0x1, 0x2, 0x4, 0x8,
     0x10, 0x20, 0x40, 0x80,
     0x100, 0x200, 0x400, 0x800,
@@ -172,7 +172,7 @@
 
 static int number_of_bits(unsigned long x, long* result)
 {
-    const unsigned long* n = nbits;
+    const unsigned long long* n = nbits;
     const int count        = sizeof(nbits) / sizeof(nbits[0]);
     *result                = 0;
     while (x >= *n) {
diff -urN eccodes-2.19.1-Source-orig/src/grib_api_internal.h eccodes-2.19.1-Source/src/grib_api_internal.h
--- eccodes-2.19.1-Source-orig/src/grib_api_internal.h	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/src/grib_api_internal.h	2021-01-12 13:10:44.839587800 +0100
@@ -86,7 +86,9 @@
 #define M_PI 3.14159265358979323846
 #endif
 
+#ifdef _MSC_VER
 #define R_OK 04 /* Needed for Windows */
+#endif
 
 #ifndef F_OK
 #define F_OK 0
diff -urN eccodes-2.19.1-Source-orig/src/grib_context.c eccodes-2.19.1-Source/src/grib_context.c
--- eccodes-2.19.1-Source-orig/src/grib_context.c	2020-11-09 14:46:27.000000000 +0100
+++ eccodes-2.19.1-Source/src/grib_context.c	2021-01-12 13:48:07.382053500 +0100
@@ -421,7 +421,7 @@
         /* On UNIX, when we read from a file we get exactly what is in the file on disk.
          * But on Windows a file can be opened in binary or text mode. In binary mode the system behaves exactly as in UNIX.
          */
-#ifdef ECCODES_ON_WINDOWS
+#ifdef _MSC_VER
         _set_fmode(_O_BINARY);
 #endif