fix: complete m4 recipe - fix_types.h with all sys types, typedef stripping

Proven recipe pattern for gnulib cross-compilation on Redox:
1. fix_types.h with guarded typedefs for ALL sys/types.h types
2. Strip raw typedefs from GL_CFLAG_GNULIB_WARNINGS after configure
3. Set cache vars for functions gnulib can't detect

Remaining: __fseterr/__freadahead stubs for linker (need relibc-level
or recipe-level .o injection)

local/scripts/gnulib-cross-fix.sh

@@ -65,8 +65,6 @@ for macro in \
     HAVE_WCWIDTH \
     HAVE_MBSRTOWCS \
     HAVE_WCSWIDTH \
-    HAVE___FSETERR \
-    HAVE_GETLOCALENAME_L \
 ; do
     perl -pi -e "s,/\\* #undef ${macro} \\*/,#define ${macro} 1," "$CONFIG_H" || true
 done