[Bug target/82626] -msse and -mfpmath=sse Causes __FLT_EVAL_METHOD__ to be -1

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82626

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I don't see any leeway in the C standard for an implementation to not define
those types at all, but we can certainly make this change, if that's the right
thing to do:

--- a/libstdc++-v3/include/c_global/cmath
+++ b/libstdc++-v3/include/c_global/cmath
@@ -1061,9 +1061,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #undef truncf
 #undef truncl

+#if 0 < __FLT_EVAL_METHOD__ && __FLT_EVAL_METHOD__ < 3
   // types
   using ::double_t;
   using ::float_t;
+#endif

   // functions
   using ::acosh;