Fix build by avoiding the _C_LABEL macro.

Change-Id: Ide367c2b65071388bd95fbc81a4ed6ae94aec4e4
diff --git a/libc/arch-x86_64/syscalls/pread64.S b/libc/arch-x86_64/syscalls/pread64.S
index 58b3176..5828a06 100644
--- a/libc/arch-x86_64/syscalls/pread64.S
+++ b/libc/arch-x86_64/syscalls/pread64.S
@@ -16,5 +16,5 @@
     ret
 END(pread64)
 
-    .globl _C_LABEL(pread)
-    .equ _C_LABEL(pread), _C_LABEL(pread64)
+    .globl pread
+    .equ pread, pread64