Bug 670499-Add gdk/fallback-c89.c

Add a fallback-c89.c for the gdk/ subdirectory as there is code that uses
functions that are introduced by C99.  This currently adds fallback
implementations for MSVC for isnan() and isinf()

Dist this "new" source file as well

gdk/Makefile.am

@@ -306,7 +306,9 @@ endif
 lib_LTLIBRARIES = libgdk-3.la
 
 MAINTAINERCLEANFILES = $(gdk_built_sources) stamp-gdkenumtypes.h
-EXTRA_DIST += $(gdk_built_sources)
+EXTRA_DIST += \
+	$(gdk_built_sources)	\
+	fallback-c89.c
 
 install-exec-hook:
 if DISABLE_EXPLICIT_DEPS

gdk/fallback-c89.c

@@ -0,0 +1,42 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 2011 Chun-wei Fan <fanc999@yahoo.com.tw>
+ *
+ * Author: Chun-wei Fan <fanc999@yahoo.com.tw>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <float.h>
+
+#ifndef HAVE_ISNAN
+/* it seems of the supported compilers only */
+/* MSVC does not have isnan(), but it does
+/* have _isnan() which does the same as isnan() */
+static inline gboolean
+isnan (double x)
+{
+  return _isnan (x);
+}
+#endif
+
+#ifndef HAVE_ISINF
+/* Unfortunately MSVC does not have finite() */
+/* but it does have _finite() which is the same */
+/* as finite() except when x is a NaN */
+static inline gboolean
+isinf (double x)
+{
+  return (!_finite (x) && !_isnan (x));
+}
+#endif