+AC_CACHE_CHECK([if $CC accepts -Wextra],
+ [ac_cv_c_Wextra],
+ [CFLAGS="-Werror ${CFLAGS_save}"
+ AC_TRY_COMPILE([],,ac_cv_c_Wextra=yes, ac_cv_c_Wextra=no)])
+
+AC_CACHE_CHECK([if $CC accepts -Wno-unused-parameter],
+ [ac_cv_c_Wno_unused_parameter],
+ [CFLAGS="-Werror ${CFLAGS_save}"
+ AC_TRY_COMPILE([],,ac_cv_c_Wno_unused_parameter=yes, ac_cv_c_Wno_unused_parameter=no)])
+
+AC_CACHE_CHECK([if $CC accepts -Wconversion],