fixup??? bugreport: add compiler info

As documented at
https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=vs-2019,
`_MSC_FULL_VER` is an integer, not a string. Therefore this fix is
needed to prevent a segmentation fault in the test t0091.1.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

compat/compiler.h

@@ -16,7 +16,8 @@ static inline void get_compiler_info(struct strbuf *info)
 #endif
 
 #ifdef _MSC_VER
-	strbuf_addf(info, "MSVC version: %s\n", _MSC_FULL_VER);
+	strbuf_addf(info, "MSVC version: %02d.%02d.%05d\n",
+		    _MSC_VER / 100, _MSC_VER % 100, _MSC_FULL_VER % 100000);
 #endif
 
 	if (len == info->len)