examples: Define _USE_MATH_DEFINES as needed

For builds using the Visual Studio headers, we must define
_USE_MATH_DEFINES in order for _M_PI to work.

1 files changed, 7 insertions, 0 deletions

diff --git a/examples/meson.build b/examples/meson.build
index 532e9bb21..256168945 100644
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -32,10 +32,17 @@ if enable_pixbuf_tests
   ]
 endif
 
+examples_cargs = []
+
+if cc.get_argument_syntax() == 'msvc'
+  examples_cargs += '-D_USE_MATH_DEFINES'
+endif
+
 foreach e: examples
   executable(
     e,
     e + '.c',
     dependencies: examples_deps,
+    c_args: examples_cargs,
   )
 endforeach