external: preserve OpenGL/OpenAL macros in the docs.

Or hide them from Doxygen so it doesn't expand them to the numeric
values.

src/MagnumExternal/OpenAL/extensions.h

@@ -38,6 +38,8 @@ extern "C" {
 #define AL_APIENTRY
 #endif
 
+#ifndef DOXYGEN_GENERATING_OUTPUT /* So the macro names are preserved in the docs */
+
 /* AL_EXT_float32 */
 #ifndef AL_EXT_float32
 #define AL_EXT_float32 1
@@ -116,6 +118,8 @@ typedef ALCchar* (AL_APIENTRY*LPALGETSTRINGISOFT)(ALCdevice*,ALCenum,ALCsizei);
 typedef ALCboolean (AL_APIENTRY*LPALRESETDEVICESOFT)(ALCdevice*,const ALCint*);
 #endif
 
+#endif
+
 #ifdef __cplusplus
 }
 #endif

src/MagnumExternal/OpenGL/GL/flextGL.h

@@ -37,6 +37,8 @@
 extern "C" {
 #endif
 
+#ifndef DOXYGEN_GENERATING_OUTPUT /* So the macro names are preserved in the docs */
+
 void flextGLInit();
 
 /* Function declaration macros */
@@ -3674,6 +3676,8 @@ GLAPI FLEXTGL_EXPORT void(APIENTRY *flextglVertexArrayVertexBuffer)(GLuint, GLui
 GLAPI FLEXTGL_EXPORT void(APIENTRY *flextglVertexArrayVertexBuffers)(GLuint, GLuint, GLsizei, const GLuint *, const GLintptr *, const GLsizei *);
 #define glVertexArrayVertexBuffers flextglVertexArrayVertexBuffers
 
+#endif
+
 #ifdef __cplusplus
 }
 #endif

src/MagnumExternal/OpenGL/GL/flextGL.h.template

@@ -38,6 +38,8 @@
 extern "C" {
 #endif
 
+#ifndef DOXYGEN_GENERATING_OUTPUT /* So the macro names are preserved in the docs */
+
 void flextGLInit();
 
 /* Function declaration macros */
@@ -96,6 +98,8 @@ GLAPI FLEXTGL_EXPORT @f.returntype\
 @end
 @end
 
+#endif
+
 #ifdef __cplusplus
 }
 #endif