Silence a bunch of macOS-specific warnings.

doc/snippets/MagnumDebugTools.cpp

@@ -100,3 +100,6 @@ CORRADE_COMPARE_WITH(actual.pixels<Color3ub>().flipped<0>(), expected,
 }
 }
 };
+
+/* To prevent macOS ranlib complaining that there are no symbols */
+int main() {}

src/Magnum/Platform/WindowlessCglApplication.h

@@ -41,6 +41,9 @@
 #include "Magnum/GL/OpenGL.h"
 #include "Magnum/Platform/Platform.h"
 
+#ifndef DOXYGEN_GENERATING_OUTPUT
+#define GL_SILENCE_DEPRECATION /* YES I KNOW, APPLE! FFS */
+#endif
 #include <OpenGL/OpenGL.h>
 #include <OpenGL/CGLTypes.h>
 #include <OpenGL/CGLCurrent.h>