Weaken libc's hidden fork versions, ltp test failed

libc/sysdeps/linux/common/fork.c

@@ -17,6 +17,6 @@ extern __typeof(fork) __libc_fork;
 _syscall0(pid_t, __libc_fork);
 libc_hidden_proto(fork)
 weak_alias(__libc_fork,fork)
-libc_hidden_def(fork)
+libc_hidden_weak(fork)
 #endif
 #endif

libc/sysdeps/linux/cris/fork.c

@@ -16,4 +16,4 @@ SYSCALL__ (__libc_fork, 0)
 __asm__("ret\n\tnop");
 libc_hidden_proto(fork)
 weak_alias(__libc_fork,fork)
-libc_hidden_def(fork)
+libc_hidden_weak(fork)

libc/sysdeps/linux/sparc/fork.S

@@ -46,4 +46,4 @@ __libc_fork:
 
 .size __libc_fork,.-__libc_fork
 weak_alias(__libc_fork,fork)
-libc_hidden_def(fork)
+libc_hidden_weak(fork)