Removed unused variable in EXAMPLE

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=262567

[[
In va_arg(3), the example function foo (section EXAMPLES, not
COMPARISON) has an unused variable: char *p.
]]

man3/stdarg.3

@@ -208,7 +208,7 @@ with each format character based on the type.
 void foo(char *fmt, ...) {
 	va_list ap;
 	int d;
-	char c, *p, *s;
+	char c, *s;
 
 	va_start(ap, fmt);
 	while (*fmt)