Improving here means do not set LIBS/CFLAGS if library is not detected.
This prevents some unknown options based to ld when host is Linux and
target is mingw32/64. Further improvements are needed if one wants this
snmp support when cross compiling to really work.
Also, to make commit bisectable, updated all autofoo files using
'autoreconf -i -f' and repatching ltmain.sh.
Also, test-driver was missing from git repo but the Makefile.in
checked in expected it to exist.
Add check for winsock2.h for socket.h replancement. Also, use this
check to add ws2_32 library. Also, switch all winsock.h references
to winsock2.h.
Add check for getuid and getpass; which are not on mingw.
Add a syslog() replacement that is basically a print(). This
is also used by vsyslog() replacement.
Comment out parts of replacement sigprocmask.c on mingw.
To support these configure.in changes, I need to rebuild all
related files with autoconf 2.68 and libtool 2.4. Hand ported
our sane-backend specific changes to newer ltmain.sh.
Chris Bagwell