Create GL context with DEBUG_BIT set when SOKOL_DEBUG is defined.

sokol_app.h

@@ -2443,6 +2443,7 @@ typedef struct {
 #define WGL_STENCIL_BITS_ARB 0x2023
 #define WGL_DOUBLE_BUFFER_ARB 0x2011
 #define WGL_SAMPLES_ARB 0x2042
+#define WGL_CONTEXT_DEBUG_BIT_ARB 0x00000001
 #define WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB 0x00000002
 #define WGL_CONTEXT_PROFILE_MASK_ARB 0x9126
 #define WGL_CONTEXT_CORE_PROFILE_BIT_ARB 0x00000001
@@ -6643,7 +6644,11 @@ _SOKOL_PRIVATE void _sapp_wgl_create_context(void) {
     const int attrs[] = {
         WGL_CONTEXT_MAJOR_VERSION_ARB, _sapp.desc.gl_major_version,
         WGL_CONTEXT_MINOR_VERSION_ARB, _sapp.desc.gl_minor_version,
+#if defined(SOKOL_DEBUG)
+        WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB | WGL_CONTEXT_DEBUG_BIT_ARB,
+#else
         WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
+#endif        
         WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_CORE_PROFILE_BIT_ARB,
         0, 0
     };