Add xp_asprintf_free() function so Win32 can still keep goats contented with

its DLLs.

src/xpdev/xpprintf.c

@@ -51,6 +51,11 @@
 /* Maximum length of a format specifier including the % */
 #define MAX_FORMAT_LEN	256
 
+void xp_asprintf_free(char *format)
+{
+	free(format);
+}
+
 int xp_printf_get_type(const char *format)
 {
 	const char	*p;

src/xpdev/xpprintf.h

@@ -71,6 +71,7 @@
 #if defined(__cplusplus)
 extern "C" {
 #endif
+void xp_asprintf_free(char *format);
 char *xp_asprintf_start(const char *format);
 char *xp_asprintf_next(char *format, int type, ...);
 char *xp_asprintf_end(char *format);