test-open: port to cygwin, which lacks Fortify
On cygwin, with gcc 4.8.3, I get this compilation warning:
In file included from ../../gltests/test-open.c:35:0:
../../gltests/test-open.h:35:1: warning: always_inline function might not be inlinable [-Wattributes]
test_open (int (*func) (char const *, int, ...), bool print)
^
On that platform, there are no Fortify enhancements, and the
internal macro __always_inline is always defined to turn on the
gcc attribute, contrary to our needs. Since relying on a __
prefix is already risky, it's better to limit the workaround of
commit
d6ba92ea to just glibc.
* tests/test-open.h (ALWAYS_INLINE): New macro.
(__always_inline): Don't abuse internal symbol on non-glibc.
Signed-off-by: Eric Blake <eblake@redhat.com>