daemon.c: make _fork_parent static inline again

The commit cf649082c7d4 ("remove forced gcc optimization") removed -O3
optimization specified in the code for the function _fork_parent, but at
the same time it removed the 'static inline' part of the function
definition. That change seems unintended and _fork_parent is not a part
of the libc interface. Make it static inline again.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

libc/unistd/daemon.c

@@ -63,7 +63,7 @@
 /* use clone() to get fork() like behavior here -- we just want to disassociate
  * from the controlling terminal
  */
-pid_t _fork_parent(void)
+static inline pid_t _fork_parent(void)
 {
 	INTERNAL_SYSCALL_DECL(err);
 	register long ret = INTERNAL_SYSCALL(clone, err, 2, CLONE_VM, 0);