c-decl.c (grokdeclarator): If -Wc++-compat, warn about a global variable with an...

c-decl.c (grokdeclarator): If -Wc++-compat, warn about a global variable with an anonymous type.

./:	* c-decl.c (grokdeclarator): If -Wc++-compat, warn about a global
	variable with an anonymous type.
fortran/:
	* cpp.c (struct gfc_cpp_option_data): Give this struct, used for
	the global variable gfc_cpp_option, a name.
testsuite/:
	* gcc.dg/Wcxx-compat-16.c: New testcase.

From-SVN: r148708