test/Sema/return.c: Cygwin does not have _longjmp().

Although Cygwin-1.7 has _longjmp(), it would not be essential for this
to distinguish Cygwin's version with <cygwin/version.h>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@116783 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed