[gtk/wip/matthiasc/listview-2: 167/179] xxx: isnanf() is some wtf

[Matthias Clasen <matthiasc src gnome org>]

commit 1f99f51c1954a5b274a4bf4830441aeed5b5038a
Author: Benjamin Otte <otte redhat com>
Date:   Mon May 25 00:07:07 2020 +0200

    xxx: isnanf() is some wtf

 gtk/fallback-c89.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
---
diff --git a/gtk/fallback-c89.c b/gtk/fallback-c89.c
index a566e3423a4..505d52e13a8 100644
--- a/gtk/fallback-c89.c
+++ b/gtk/fallback-c89.c
@@ -93,15 +93,27 @@ isnan (double x)
 #endif
 
 #ifndef HAVE_DECL_ISNANF
+#if 1
+#define isnanf(x) isnan(x)
+#else
 /* it seems of the supported compilers only
  * MSVC does not have isnanf(), but it does
  * have _isnanf() which does the same as isnanf()
  */
+#ifdef _MSC_VER
 static inline gboolean
 isnanf (float x)
 {
   return _isnanf (x);
 }
+#elif defined (__GNUC__)
+/* gcc has an intern function that it warns about when
+ * using -Wshadow but no header properly declares it,
+ * so we do it instead.
+ */
+extern int isnanf (float x);
+#endif
+#endif
 #endif
 
 #ifndef INFINITY