Add COMPILER_RT_ABI attribute to declarations of builtin functions in unittests

Summary:
This makes their local declarations match their definitions for ARM targets,
where they have a different calling convention.

This really only affects functions that use floating point types (since the
runtime functions use soft-float, and some targets may default to hard-float)
but it seemed good to make it uniform and do the int-only ones too.

Differential Revision: http://reviews.llvm.org/D9062

llvm-svn: 235722
diff --git a/compiler-rt/test/builtins/Unit/floatunssisfvfp_test.c b/compiler-rt/test/builtins/Unit/floatunssisfvfp_test.c
index 917061a..47f837c 100644
--- a/compiler-rt/test/builtins/Unit/floatunssisfvfp_test.c
+++ b/compiler-rt/test/builtins/Unit/floatunssisfvfp_test.c
@@ -14,9 +14,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
+#include "int_lib.h"
 
-
-extern float __floatunssisfvfp(unsigned int a);
+extern COMPILER_RT_ABI float __floatunssisfvfp(unsigned int a);
 
 #if __arm__
 int test__floatunssisfvfp(unsigned int a)