libsdl2 fails to build on lion

[rmottola (Riccardo)]

I suppose it is an issue with the code using an unsupportedgetter/property.

I Think there should be a more compatible way to get the CF color from the NS version, being toll-free bridged?

:info:build /bin/sh ./libtool --tag=CC --mode=compile /usr/bin/clang -pipe -Os -arch x86_64 -I/opt/local/include -DUSING_GENERATED_CONFIG_H -Iinclude -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_libsdl2/libsdl2/work/SDL2-2.0.9/include -idirafter /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_libsdl2/libsdl2/work/SDL2-2.0.9/src/video/khronos  -mmmx -msse -msse2 -msse3 -Wall -DTARGET_API_MAC_CARBON -DTARGET_API_MAC_OSX -fvisibility=hidden -Wdeclaration-after-statement -Werror=declaration-after-statement -D_THREAD_SAFE -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_libsdl2/libsdl2/work/SDL2-2.0.9/src/hidapi/hidapi -MMD -MT build/SDL_syssem.lo -c /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_libsdl2/libsdl2/work/SDL2-2.0.9/src/thread/pthread/SDL_syssem.c -o build/SDL_syssem.lo
:info:build /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_libsdl2/libsdl2/work/SDL2-2.0.9/src/video/cocoa/SDL_cocoawindow.m:1178:53: error: property 'CGColor' not found on object of type 'NSColor *'
:info:build     self.layer.backgroundColor = NSColor.blackColor.CGColor;
:info:build                                                     ^
:info:build 1 error generated.
:info:build make: *** [build/SDL_cocoawindow.lo] Error 1
:info:build make: *** Waiting for unfinished jobs....

[ryandesign (Ryan Carsten Schmidt)]

Duplicate of #57540.