For libm, use a macro for aliasing symbols.

Change-Id: Ibd42ebc387c2bf3eba9aa96091770915b4b34184
diff --git a/libm/arm/e_sqrt.S b/libm/arm/e_sqrt.S
index 669212f..17312f5 100644
--- a/libm/arm/e_sqrt.S
+++ b/libm/arm/e_sqrt.S
@@ -39,7 +39,4 @@
     bx          lr
 END(sqrt)
 
-#if LDBL_MANT_DIG == 53
-    .weak       sqrtl
-    .equ        sqrtl, sqrt
-#endif
+ALIAS_SYMBOL(sqrtl, sqrt);