Remove useless _C_LABEL from our assembler source.

Change-Id: I41a9181537c70ecc69ef8035132c9a83811a40d0
diff --git a/libc/arch-x86_64/bionic/sigsetjmp.S b/libc/arch-x86_64/bionic/sigsetjmp.S
index 842d6ff..174222f 100644
--- a/libc/arch-x86_64/bionic/sigsetjmp.S
+++ b/libc/arch-x86_64/bionic/sigsetjmp.S
@@ -58,9 +58,9 @@
 	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)
@@ -87,9 +87,9 @@
 
 	movq	(_JB_SIGMASK * 8)(%rdi),%rdi
 #ifdef __PIC__
-	call	PIC_PLT(_C_LABEL(sigsetmask))
+	call	PIC_PLT(sigsetmask)
 #else
-	call	_C_LABEL(sigsetmask)
+	call	sigsetmask
 #endif
 2:	popq	%rax
 	movq	(_JB_RBX * 8)(%r12),%rbx