Hello!
I had the same problem. "__attribute__((__packed__))" is a type of GCC-extension. I had set "-gcc"- language option (http://processors.wiki.ti.com/index.php/GCC_Extensions_in_TI_Compilers) but compiler (v6.1.0) sent error message. But into controlSUITE there are header files which use this type (for example ti\controlSUITE\device_support\f28m35x\v160\MWare\third_party\lwip-1.3.2\ports\C2000\include\arch\cc.h). Oddly...
Regards,
Igor