Save and restore CFLAGS properly inside libtool.m4 macros.

Save and restore CFLAGS properly inside libtool.m4 macros.

* libltdl/m4/libtool.m4 (_LT_CMD_GLOBAL_SYMBOLS): Use different
temporary variables for saved and restored values of $LIBS,
$CFLAGS, to avoid overlap with the *_CONFIG macros.
(_LT_LANG_CXX_CONFIG, _LT_LANG_F77_CONFIG, _LT_LANG_FC_CONFIG)
(_LT_LANG_GCJ_CONFIG, _LT_LANG_RC_CONFIG): Also save and restore
$CFLAGS, and override it with per-language flags, so that in
case output_verbose_link_cmd uses $CFLAGS, the right flags are
used.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>