Remove useless _C_LABEL from our assembler source.

Change-Id: I41a9181537c70ecc69ef8035132c9a83811a40d0
diff --git a/libc/arch-x86_64/bionic/setjmp.S b/libc/arch-x86_64/bionic/setjmp.S
index 4dd9028..3f4a432 100644
--- a/libc/arch-x86_64/bionic/setjmp.S
+++ b/libc/arch-x86_64/bionic/setjmp.S
@@ -54,9 +54,9 @@
 	pushq	%rdi
 	xorq	%rdi,%rdi
 #ifdef __PIC__
-	call	PIC_PLT(_C_LABEL(sigblock))
+	call	PIC_PLT(sigblock)
 #else
-	call	_C_LABEL(sigblock)
+	call	sigblock
 #endif
 	popq	%rdi
 	movq	%rax,(_JB_SIGMASK * 8)(%rdi)
@@ -82,9 +82,9 @@
 	movq	(_JB_SIGMASK * 8)(%rdi),%rdi
 	pushq	%r8
 #ifdef __PIC__
-	call	PIC_PLT(_C_LABEL(sigsetmask))
+	call	PIC_PLT(sigsetmask)
 #else
-	call	_C_LABEL(sigsetmask)
+	call	sigsetmask
 #endif
 	popq	%r8
 	movq	(_JB_RBX * 8)(%r12),%rbx