For libm, use a macro for aliasing symbols.

Change-Id: Ibd42ebc387c2bf3eba9aa96091770915b4b34184
diff --git a/libm/x86/e_acos.S b/libm/x86/e_acos.S
index a429481..fa61853 100644
--- a/libm/x86/e_acos.S
+++ b/libm/x86/e_acos.S
@@ -388,8 +388,7 @@
 # -- End  acos
 
 # Start file scope ASM
-.weak acosl
-.equ acosl, acos
+ALIAS_SYMBOL(acosl, acos);
 # End file scope ASM
 	.section .rodata, "a"
 	.align 16