Improve virtual void* Fl_Gl_Window_Driver::GetProcAddress(procName)

src/Fl_Gl_Window.cxx

@@ -521,28 +521,21 @@ char Fl_Gl_Window_Driver::swap_type() {return UNDEFINED;}
 
 
 void* Fl_Gl_Window_Driver::GetProcAddress(const char *procName) {
-#if (HAVE_DLSYM && HAVE_DLFCN_H)
-  char symbol[1024];
-
-  snprintf(symbol, sizeof(symbol), "_%s", procName);
-
-#    ifdef RTLD_DEFAULT
-  return dlsym(RTLD_DEFAULT, symbol);
-
-#    else // No RTLD_DEFAULT support, so open the current a.out symbols...
-  static void *rtld_default = dlopen(0, RTLD_LAZY);
-
-  if (rtld_default) return dlsym(rtld_default, symbol);
-  else return 0;
-
-#    endif // RTLD_DEFAULT
-
-#elif defined(HAVE_GLXGETPROCADDRESSARB)
+#if defined(HAVE_GLXGETPROCADDRESSARB)
   return (void*)glXGetProcAddressARB((const GLubyte *)procName);
+  
+#elif (HAVE_DLSYM && HAVE_DLFCN_H)
+#  ifdef RTLD_DEFAULT
+      void *rtld_default = RTLD_DEFAULT;
+#  else
+      static void *rtld_default = dlopen(0, RTLD_LAZY);
+#  endif
+  char symbol[1024];
+  snprintf(symbol, sizeof(symbol), "_%s", procName);
+  return dlsym(rtld_default, symbol);
 
-#else
-  return 0;
 #endif // HAVE_DLSYM
+  return NULL;
 }
 
 Fl_Font_Descriptor** Fl_Gl_Window_Driver::fontnum_to_fontdescriptor(int fnum) {

src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.H

@@ -42,6 +42,7 @@ class Fl_Cocoa_Gl_Window_Driver : public Fl_Gl_Window_Driver {
   virtual char *alpha_mask_for_string(const char *str, int n, int w, int h, Fl_Fontsize fs);
   virtual Fl_RGB_Image* capture_gl_rectangle(int x, int y, int w, int h);
   virtual bool need_scissor() { return true; }
+  virtual void* GetProcAddress(const char *procName);
   void apply_scissor();
 };
 

src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.cxx

@@ -25,6 +25,7 @@
 #include <FL/Fl_Graphics_Driver.H>
 #include <OpenGL/OpenGL.h>
 #include <FL/Fl_Image_Surface.H>
+#include <dlfcn.h>
 
 extern void gl_texture_reset();
 
@@ -293,6 +294,11 @@ Fl_RGB_Image* Fl_Cocoa_Gl_Window_Driver::capture_gl_rectangle(int x, int y, int
 }
 
 
+void* Fl_Cocoa_Gl_Window_Driver::GetProcAddress(const char *procName) {
+  return dlsym(RTLD_DEFAULT, procName);
+}
+
+
 FL_EXPORT NSOpenGLContext *fl_mac_glcontext(GLContext rc) {
   return (NSOpenGLContext*)rc;
 }