Explicitly test for broken strnvis.

NetBSD added an strnvis and unfortunately made it incompatible with the
existing one in OpenBSD and Linux's libbsd (the former having existed
for over ten years). Despite this incompatibility being reported during
development (see http://gnats.netbsd.org/44977) they still shipped it.
Even more unfortunately FreeBSD and later MacOS picked up this incompatible
implementation.  Try to detect this mess, and assume the only safe option
if we're cross compiling.

OpenBSD 2.9 (2001): strnvis(char *dst, const char *src, size_t dlen, int flag);
NetBSD 6.0 (2012):  strnvis(char *dst, size_t dlen, const char *src, int flag);

ok djm@

0 files changed, 0 insertions, 0 deletions