i386/bits/syscalls.h: allow immediate values as 6th syscall arg

Allow use of immedate values as the 6th syscall argument. Otherwise we must
store the arg on memory. This gives gcc more options to optimize better.

This also works around an issue with posix_fallocate.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

libc/sysdeps/linux/i386/bits/syscalls.h

@@ -136,7 +136,7 @@ __asm__ (
 #define ASMFMT_5(arg1, arg2, arg3, arg4, arg5) \
 	, "a" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
 #define ASMFMT_6(arg1, arg2, arg3, arg4, arg5, arg6) \
-	, "a" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5), "m" (arg6)
+	, "a" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5), "g" (arg6)
 
 #else /* !PIC */