if test "x$GCC" = xyes; then
CFLAGS="-std=c89 -pedantic -Wall -Wextra -Werror $CFLAGS"
- CFLAGS="-D_XOPEN_SOURCE=500 -Wno-error=int-to-pointer-cast $CFLAGS"
+ CFLAGS="-Wno-error=int-to-pointer-cast $CFLAGS"
+ CPPFLAGS="-D_XOPEN_SOURCE=500 $CPPFLAGS"
# Additional security flags.
CFLAGS="$CFLAGS -Wformat -Wformat-security -Werror=format-security"
CFLAGS="$CFLAGS -fstack-protector-all -Wstack-protector"