Define std::strtoull for MSVC compiler.

This function is used in Oracle backend.

src/core/soci-platform.h

@@ -22,18 +22,25 @@
 #define HAVE_SNPRINTF 1
 #define snprintf _snprintf
 
-// Define if you have the strtoll variants.
+// Define if you have the strtoll and strtoull variants.
 #if _MSC_VER >= 1300
 # define HAVE_STRTOLL 1
+# define HAVE_STRTOULL 1
 namespace std {
     inline long long strtoll(char const* str, char** str_end, int base)
     {
         return _strtoi64(str, str_end, base);
     }
+
+    inline unsigned long long strtoull(char const* str, char** str_end, int base)
+    {
+        return _strtoui64(str, str_end, base);
+    }
 }
 #else
 # undef HAVE_STRTOLL
-# error "Visual C++ versions prior 1300 don't support strtoi64"
+# undef HAVE_STRTOULL
+# error "Visual C++ versions prior 1300 don't support _strtoi64 and _strtoui64"
 #endif // _MSC_VER >= 1300
 #endif // _MSC_VER