Change default compiler for gnu-cobol to GCC

The default clang version bundled with Mac OS X causes a reproduceable error when compiling e.g. CobolUnit.
The resulting message is:
error: indirect goto in function with no address-of-label expressions
This patch uses GCC as default compiler which works fine.
Removed env :std - not needed
Do not depend on GCC as requested
Added devel version of GNU-Cobol which is compatible with clang
Fixed version number
gnu-cobol: update 1.1 bottle.