- irix* | solaris*) gl_cv_func_isnanf_works="guessing no";;
- *) gl_cv_func_isnanf_works="guessing yes";;
+ irix* | solaris*) gl_cv_func_isnanf_works="guessing no" ;;
+ mingw*) # Guess yes on mingw, no on MSVC.
+ AC_EGREP_CPP([Known], [
+#ifdef __MINGW32__
+ Known
+#endif
+ ],
+ [gl_cv_func_isnanf_works="guessing yes"],
+ [gl_cv_func_isnanf_works="guessing no"])
+ ;;
+ *) gl_cv_func_isnanf_works="guessing yes" ;;