# endif
#endif
+/* If on legacy platforms, and not using gcc, some C99 math interfaces
+ * might be missing, turn them off so that the emulations hopefully
+ * kick in. This is admittedly nasty, and fragile, but the alternative
+ * is to have Configure scans for all the 40+ interfaces. */
+#ifndef __GNUC__
+
/* HP-UX on PA-RISC is missing certain C99 math functions,
* but on IA64 (Integrity) these do exist. */
-#if defined(__hpux) && defined(__hppa)
-# undef c99_fma
-# undef c99_nexttoward
-# undef c99_tgamma
+# if defined(__hpux) && defined(__hppa)
+# undef c99_fma
+# undef c99_nexttoward
+# undef c99_tgamma
+# endif
+
+# if defined(__irix__)
+# undef c99_ilogb
+# undef c99_exp2
+# endif
+
+# if defined(__osf__) /* Tru64 */
+# undef c99_fdim
+# undef c99_fma
+# undef c99_fmax
+# undef c99_fmin
+# undef c99_fpclassify
+# undef c99_isfinite
+# undef c99_isinf
+# undef c99_isunordered
+# undef c99_lrint
+# undef c99_nearbyint
+# undef c99_nexttoward
+# undef c99_remquo
+# undef c99_rint
+# undef c99_round
+# undef c99_scalbn
+# endif
+
#endif
/* XXX Regarding C99 math.h, Win32 seems to be missing these: