[build] -D_DEFAULT_SOURCE consistency in builds

(previously defined in src/CMakeLists.txt)

SConstruct

@@ -297,6 +297,7 @@ env.Append(CPPFLAGS = [
 	'-D_FILE_OFFSET_BITS=64',
 	'-D_LARGEFILE_SOURCE',
 	'-D_LARGE_FILES',
+	'-D_DEFAULT_SOURCE',
 	'-D_GNU_SOURCE',
 ])
 

configure.ac

@@ -1535,7 +1535,7 @@ AC_ARG_ENABLE([lfs],
 )
 AC_MSG_RESULT([$ENABLE_LFS])
 if test "$ENABLE_LFS" = yes; then
-  CPPFLAGS="${CPPFLAGS} -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGE_FILES"
+  CPPFLAGS="${CPPFLAGS} -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGE_FILES -D_DEFAULT_SOURCE"
   AC_SYS_LARGEFILE
 fi
 

src/meson.build

@@ -13,6 +13,7 @@ defs = [
 	'-D_FILE_OFFSET_BITS=64',
 	'-D_LARGEFILE_SOURCE',
 	'-D_LARGE_FILES',
+	'-D_DEFAULT_SOURCE',
 	'-D_GNU_SOURCE',
 ]