Roll libxml to 2.9.3

third_party/libxml/win32/config.h

 #ifndef __LIBXML_WIN32_CONFIG__
 #define __LIBXML_WIN32_CONFIG__
 
 #define HAVE_CTYPE_H
 #define HAVE_STDARG_H
 #define HAVE_MALLOC_H
 #define HAVE_ERRNO_H
-#define SEND_ARG2_CAST
-#define GETHOSTBYNAME_ARG_CAST
+#define HAVE_STDINT_H
 
 #if defined(_WIN32_WCE)
 #undef HAVE_ERRNO_H
 #include <windows.h>
 #include "wincecompat.h"
 #else
 #define HAVE_SYS_STAT_H
 #define HAVE__STAT
 #define HAVE_STAT
 #define HAVE_STDLIB_H
@@ skipping 70 matching lines @@
         }
     } else {
         return 0;
     }
 }
 #endif
 #endif /* _MSC_VER */
 
 #if defined(_MSC_VER)
 #define mkdir(p,m) _mkdir(p)
-#if _MSC_VER < 1900
 #define snprintf _snprintf
-#endif

[Peter Kasting, 2016/03/03 22:32:53]

Removing these two lines is what broke the Visual Studio 2015 build.  If they
are restored, things build correctly.

AFAICT, upstream has both include/win32config.h and win32/VC10/config.h, which
are almost identical except that the latter is missing this change, and there
are minor differences in the #defines atop the files.  The deltas in this patch
set suggest we moved from this being a copy of the former to a copy of the
latter.  I'm not sure whether that's correct.

Honestly, I don't understand precisely what upstream intends the differences
here to be.  I suspect it is an error to have both of these files and have them
only slightly different.  Probably upstream needs to just use one, from one
place.

 #if _MSC_VER < 1500
 #define vsnprintf(b,c,f,a) _vsnprintf(b,c,f,a)
 #endif
 #elif defined(__MINGW32__)
 #define mkdir(p,m) _mkdir(p)
 #endif
 
 /* Threading API to use should be specified here for compatibility reasons.
    This is however best specified on the compiler's command-line. */
 #if defined(LIBXML_THREAD_ENABLED)
 #if !defined(HAVE_PTHREAD_H) && !defined(HAVE_WIN32_THREADS) && !defined(_WIN32_WCE)
 #define HAVE_WIN32_THREADS
 #endif
 #endif
 
 /* Some third-party libraries far from our control assume the following
    is defined, which it is not if we don't include windows.h. */
 #if !defined(FALSE)
 #define FALSE 0
 #endif
 #if !defined(TRUE)
 #define TRUE (!(FALSE))
 #endif
 
 #endif /* __LIBXML_WIN32_CONFIG__ */