For libm, use a macro for aliasing symbols.

Change-Id: Ibd42ebc387c2bf3eba9aa96091770915b4b34184
diff --git a/libm/x86/s_cbrt.S b/libm/x86/s_cbrt.S
index d065de2..0c98c99 100644
--- a/libm/x86/s_cbrt.S
+++ b/libm/x86/s_cbrt.S
@@ -225,8 +225,7 @@
 # -- End  cbrt
 
 # Start file scope ASM
-.weak cbrtl
-.equ cbrtl, cbrt
+ALIAS_SYMBOL(cbrtl, cbrt);
 # End file scope ASM
 	.section .rodata, "a"
 	.align 16