MSVC: Define _USE_MATH_DEFINES via meson.build

This way M_PI and other constants are available everywhere.
The constants are behind a preprocessor macro because they
aren't part of standard C.

meson.build

@@ -102,6 +102,7 @@ if cc.get_id() == 'msvc'
                         language : ['c', 'cpp'])
   add_project_arguments(['-D_CRT_SECURE_NO_WARNINGS',
                          '-D_CRT_NONSTDC_NO_WARNINGS',
+                         '-D_USE_MATH_DEFINES',
                         ], language : ['c', 'cpp'])
 endif
 

perf/micro/pythagoras-tree.c

@@ -24,7 +24,7 @@
  */
 
 #include "cairo-perf.h"
-#define _USE_MATH_DEFINES /* for M_SQRT2 on win32 */
+
 #include <math.h>
 
 static void

src/cairoint.h

@@ -55,9 +55,6 @@
 #include <stdarg.h>
 #include <stddef.h>
 
-#ifdef _MSC_VER
-#define _USE_MATH_DEFINES
-#endif
 #include <math.h>
 #include <limits.h>
 #include <stdio.h>

test/cairo-test.h

@@ -55,7 +55,6 @@ typedef unsigned __int64 uint64_t;
 #endif
 
 #ifdef _MSC_VER
-#define _USE_MATH_DEFINES
 #include <float.h>
 #endif
 

util/cairo-script/cairo-script-operators.c

@@ -46,10 +46,6 @@
 #include <stdlib.h> /* mkstemp */
 #include <string.h>
 
-#ifdef _MSC_VER
-#define _USE_MATH_DEFINES /* for M_LN2, M_PI and M_SQRT2 on win32 */
-#endif
-
 #include <math.h>
 #include <limits.h> /* INT_MAX */
 #include <assert.h>