gtk/fallback-c89.c: Add fallback for fmin()

fmin() is a function that is introduced with C99/C++11, so check for the
presence of it and provide a simple implementation for it if it does not
exist.

Also update the config.h.win32.in template accordingly, since this
function is provided on Visual Studio 2013 or later.

config.h.meson

@@ -44,6 +44,9 @@
 /* Define to 1 if you have the `flockfile' function. */
 #mesondefine HAVE_FLOCKFILE
 
+/* Define to 1 if you have the `fmin' function. */
+#mesondefine HAVE_FMIN
+
 /* Define to 1 if you have the <ftw.h> header file. */
 #mesondefine HAVE_FTW_H
 

config.h.win32.in

@@ -52,6 +52,11 @@
 /* Define to 1 if you have the `flockfile' function. */
 #undef HAVE_FLOCKFILE
 
+/* Define to 1 if you have the `fmin' function. */
+#if !defined (_MSC_VER) || (_MSC_VER >= 1800)
+# define HAVE_FMIN 1
+#endif
+
 /* Define to 1 if you have the <ftw.h> header file. */
 /* #undef HAVE_FTW_H */
 

configure.ac

@@ -843,7 +843,7 @@ AC_TYPE_UID_T
 # Check for round(), rint(), isnan() and isinf()
 # Check for log2(), exp2(), nearbyint() and trunc()
 AC_CHECK_LIB(m,round,,)
-AC_CHECK_FUNCS(round rint nearbyint sincos exp2 log2 trunc)
+AC_CHECK_FUNCS(round rint nearbyint sincos exp2 log2 trunc fmin)
 AC_CHECK_DECLS([isnan, isinf], [], [], [[#include <math.h>]])
 
 AC_MSG_CHECKING(whether to build dynamic modules)

gtk/fallback-c89.c

@@ -126,3 +126,11 @@ isnan (double x)
   return _isnan (x);
 }
 #endif
+
+#ifndef HAVE_FMIN
+static inline double
+fmin (double x, double y)
+{
+  return x < y ? x : y;
+}
+#endif

gtk/gtkscrolledwindow.c

@@ -48,7 +48,7 @@
 #include "gtkprogresstrackerprivate.h"
 #include "gtksettingsprivate.h"
 
-#include <math.h>
+#include "fallback-c89.c"
 
 /**
  * SECTION:gtkscrolledwindow

meson.build

@@ -252,6 +252,7 @@ check_functions = [
   'sincos',
   'trunc',
   'localtime_r',
+  'fmin',
 ]
 
 foreach func : check_functions