Port the unit test framework to windows

Backport from 6.0.14 to 5.6.0

Original code from Guilhem Bichot

unittest/mytap/tap.c

@@ -19,7 +19,7 @@
 
 #include "tap.h"
 
-#include "my_config.h"
+#include "my_global.h"
 
 #include <stdlib.h>
 #include <stdarg.h>
@@ -27,6 +27,16 @@
 #include <string.h>
 #include <signal.h>
 
+/*
+  Visual Studio 2003 does not know vsnprintf but knows _vsnprintf.
+  We don't put this #define in config-win.h because we prefer
+  my_vsnprintf everywhere instead, except when linking with libmysys
+  is not desirable - the case here.
+*/
+#if defined(_MSC_VER) && ( _MSC_VER == 1310 )
+#define vsnprintf _vsnprintf
+#endif
+
 /**
    @defgroup MyTAP_Internal MyTAP Internals
 
@@ -150,8 +160,10 @@ static signal_entry install_signal[]= {
   { SIGILL,  handle_core_signal },
   { SIGABRT, handle_core_signal },
   { SIGFPE,  handle_core_signal },
-  { SIGSEGV, handle_core_signal },
-  { SIGBUS,  handle_core_signal }
+  { SIGSEGV, handle_core_signal }
+#ifdef SIGBUS
+  , { SIGBUS,  handle_core_signal }
+#endif
 #ifdef SIGXCPU
   , { SIGXCPU, handle_core_signal }
 #endif
@@ -166,13 +178,22 @@ static signal_entry install_signal[]= {
 #endif
 };
 
+int skip_big_tests= 1;
+
 void
 plan(int const count)
 {
+  char *config= getenv("MYTAP_CONFIG");
+  size_t i;
+
+  if (config)
+    skip_big_tests= strcmp(config, "big");
+
+  setvbuf(tapout, 0, _IONBF, 0);  /* provide output at once */
   /*
     Install signal handler
   */
-  size_t i;
+
   for (i= 0; i < sizeof(install_signal)/sizeof(*install_signal); ++i)
     signal(install_signal[i].signo, install_signal[i].handler);