Windows compatibility fixes

VS2013 has trouble with relative include paths for apps/openssl, so move
certhash_win/apps_win.c back to apps/openssl.

gmtime_r on mingw64 fails with negative time_t, override

gmtime_s fails all of the time unit tests, override

SHUT_RD/WR are defined in newer mingw64 headers, check before overriding

apps/openssl/Makefile.am

@@ -60,11 +60,11 @@ openssl_SOURCES += x509.c
 if BUILD_CERTHASH
 openssl_SOURCES += certhash.c
 else
-openssl_SOURCES += compat/certhash_win.c
+openssl_SOURCES += certhash_win.c
 endif
 
 if HOST_WIN
-openssl_SOURCES += compat/apps_win.c
+openssl_SOURCES += apps_win.c
 else
 openssl_SOURCES += apps_posix.c
 endif

apps/openssl/apps_win.c

@@ -10,7 +10,7 @@
 #include <io.h>
 #include <fcntl.h>
 
-#include <apps.h>
+#include "apps.h"
 
 double
 app_tminterval(int stop, int usertime)