For libm, use a macro for aliasing symbols.

Change-Id: Ibd42ebc387c2bf3eba9aa96091770915b4b34184
diff --git a/libm/x86/sqrt.S b/libm/x86/sqrt.S
index 3e459ce..c9d434d 100644
--- a/libm/x86/sqrt.S
+++ b/libm/x86/sqrt.S
@@ -40,5 +40,4 @@
 	ret
 END(sqrt)
 
-.globl sqrtl;
-.equ sqrtl, sqrt;
+ALIAS_SYMBOL(sqrtl, sqrt);