+AC_CACHE_CHECK(whether compiler supports -Wno-pointer-sign, nmh_cv_has_noptrsign,
+[nmh_saved_cflags="$CFLAGS"
+ CFLAGS="$CFLAGS -Wno-pointer-sign"
+ AC_TRY_COMPILE([],[],nmh_cv_has_noptrsign=yes,nmh_cv_has_noptrsign=no)
+ CFLAGS="$nmh_saved_cflags"])
+