[[ VS2015 ]] Tweak libzip so it builds using VS2015

This patch tweaks libzip to ensure it compiles under VS2015. It
adds a macro to redefine the name of the function snprintf
appropriately and workaround to a bug in the MSVS CRT includes
which cause the wrong binding of putc when DISABLE_PERFCRIT_LOCKS
is defined.

Author: runrevmark

libzip/src/zip_dirent.c

@@ -42,6 +42,11 @@
 
 #ifndef _WINDOWS
 #include <unistd.h>
+#else
+// A bug in the MSVS2015 CRT means that when _CRT_DISABLE_PERFCRIT_LOCKS is
+// set, this function binds incorrectly.
+#undef putc
+#define putc fputc
 #endif
 
 #include <sys/types.h>

libzip/src/zipintw32.h

@@ -15,7 +15,6 @@ typedef unsigned short mode_t;
 
 #define fseeko fseek
 #define strcasecmp _stricmp
-#define snprintf _snprintf
 #define fdopen _fdopen
 #define strdup _strdup
 #define fileno _fileno