Switch sigpending over to rt_sigpending.

Change-Id: I7b28984796b5fb343cfbcc47e0afc3a84293d417
diff --git a/libc/arch-arm/syscalls/sigpending.S b/libc/arch-arm/syscalls/__rt_sigpending.S
similarity index 76%
rename from libc/arch-arm/syscalls/sigpending.S
rename to libc/arch-arm/syscalls/__rt_sigpending.S
index ba667a0..0e0be3a 100644
--- a/libc/arch-arm/syscalls/sigpending.S
+++ b/libc/arch-arm/syscalls/__rt_sigpending.S
@@ -3,13 +3,13 @@
 #include <linux/err.h>
 #include <machine/asm.h>
 
-ENTRY(sigpending)
+ENTRY(__rt_sigpending)
     mov     ip, r7
-    ldr     r7, =__NR_sigpending
+    ldr     r7, =__NR_rt_sigpending
     swi     #0
     mov     r7, ip
     cmn     r0, #(MAX_ERRNO + 1)
     bxls    lr
     neg     r0, r0
     b       __set_errno
-END(sigpending)
+END(__rt_sigpending)