Build fix for wxOSX build with 10.6 SDK after last commit

OpenGL core profile constants only exist in 10.7 SDK, don't use them when
compiling with 10.6 one.

See #16402.

src/osx/cocoa/glcanvas.mm

@@ -234,12 +234,16 @@ WXGLPixelFormat WXGLChoosePixelFormat(const int *attribList)
                     break;
 
                 case WX_GL_CORE_PROFILE:
+                    // NSOpenGLPFAOpenGLProfile and NSOpenGLProfileVersion3_2Core
+                    // are only defined in 10.7 SDK, we can't support this
+                    // attribute with 10.6.
+#if MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
                     data[p++] = NSOpenGLPFAOpenGLProfile;
                     // request an OpenGL core profile
                     // will use the highest available OpenGL version
                     // which will be at least 3.2
                     data[p++] = NSOpenGLProfileVersion3_2Core;
-
+#endif // 10.7+
                     break;
             }
         }