CMake support added

cmake/UseSystemExtensions.cmake

@@ -0,0 +1,81 @@
+cmake_minimum_required(VERSION 3.12)
+
+include(CheckCSourceCompiles)
+
+check_c_source_compiles("
+    int main()
+    {
+    #ifndef _FORTIFY_SOURCE
+        return 0;
+    #else
+        this_is_an_error;
+    #endif
+    }"
+    DODEFINE_FORTIFY_SOURCE)
+check_c_source_compiles("
+    #include <wchar.h>
+    mbstate_t x;
+    int main() { return 0; }"
+    HAVE_MBSTATE)
+if(NOT HAVE_MBSTATE)
+    check_c_source_compiles("
+        #define _XOPEN_SOURCE 500
+        #include <wchar.h>
+        mbstate_t x;
+        int main() { return 0; }"
+        DODEFINE_XOPEN_SOURCE)
+endif()
+check_c_source_compiles("
+    #define __EXTENSIONS__ 1
+    #include <stdio.h>
+    #ifdef HAVE_SYS_TYPES_H
+    # include <sys/types.h>
+    #endif
+    #ifdef HAVE_SYS_STAT_H
+    # include <sys/stat.h>
+    #endif
+    #ifdef STDC_HEADERS
+    # include <stdlib.h>
+    # include <stddef.h>
+    #else
+    # ifdef HAVE_STDLIB_H
+    #  include <stdlib.h>
+    # endif
+    #endif
+    #ifdef HAVE_STRING_H
+    # if !defined STDC_HEADERS && defined HAVE_MEMORY_H
+    #  include <memory.h>
+    # endif
+    # include <string.h>
+    #endif
+    #ifdef HAVE_STRINGS_H
+    # include <strings.h>
+    #endif
+    #ifdef HAVE_INTTYPES_H
+    # include <inttypes.h>
+    #endif
+    #ifdef HAVE_STDINT_H
+    # include <stdint.h>
+    #endif
+    #ifdef HAVE_UNISTD_H
+    # include <unistd.h>
+    #endif
+    int main() { return 0; }"
+    DODEFINE_EXTENSIONS)
+
+add_compile_definitions(
+    _ALL_SOURCE
+    _DARWIN_C_SOURCE
+    _GNU_SOURCE
+    _POSIX_PTHREAD_SEMANTICS
+    __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+    __STDC_WANT_IEC_60559_BFP_EXT__
+    __STDC_WANT_IEC_60559_DFP_EXT__
+    __STDC_WANT_IEC_60559_FUNCS_EXT__
+    __STDC_WANT_IEC_60559_TYPES_EXT__
+    __STDC_WANT_LIB_EXT2__
+    __STDC_WANT_MATH_SPEC_FUNCS__
+    _TANDEM_SOURCE
+    $<$<AND:$<BOOL:${DODEFINE_FORTIFY_SOURCE}>,$<OR:$<CONFIG:Release>,$<CONFIG:RelWithDebInfo>>>:_FORTIFY_SOURCE=2>
+    $<$<BOOL:${DODEFINE_XOPEN_SOURCE}>:_XOPEN_SOURCE=500>
+    $<$<BOOL:${DODEFINE_EXTENTIONS}>:__EXTENSIONS__>)