Disable wxUSE_ACTIVITYINDICATOR for non-MSVC compilers under MSW.

Don't give errors in the default configuration for MinGW makefile builds in
which wxUSE_GRAPHICS_CONTEXT is disabled, but wxUSE_ACTIVITYINDICATOR is
enabled.

Instead, disable wxUSE_ACTIVITYINDICATOR implicitly for them, this is not
ideal but better than broken build.

include/wx/chkconf.h

@@ -2247,15 +2247,6 @@
 #   endif
 #endif /* wxUSE_PREFERENCES_EDITOR */
 
-#if wxUSE_ACTIVITYINDICATOR && !wxUSE_GRAPHICS_CONTEXT
-#   ifdef wxABORT_ON_CONFIG_ERROR
-#       error "wxUSE_ACTIVITYINDICATOR requires wxGraphicsContext"
-#   else
-#       undef wxUSE_ACTIVITYINDICATOR
-#       define wxUSE_ACTIVITYINDICATOR 0
-#   endif
-#endif /* wxUSE_ACTIVITYINDICATOR */
-
 #endif /* wxUSE_GUI */
 
 #endif /* _WX_CHKCONF_H_ */