re PR c/6024 (GCC fails to diagnose mismatch of enum types in prototype/function)

re PR c/6024 (GCC fails to diagnose mismatch of enum types in prototype/function)

	PR c/6024
	* c-typeck.c (comptypes): Only treat enumerated types in the same
	translation unit as compatible with each other when they are the
	same type.
	* doc/extend.texi: Update.

f:
	* com.h (ffecom_gfrt_basictype): Correct return type.

testsuite:
	* gcc.dg/enum-compat-1.c: New test.
	* gcc.c-torture/execute/builtin-types-compatible-p.c: Update.

From-SVN: r75521