[builtins] Build x86_64 with GENERIC_TF_SOURCES

llvm-svn: 358706
diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
index ee828aa..d0bd07b 100644
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -239,6 +239,7 @@
 
 if (NOT MSVC)
   set(x86_64_SOURCES
+    ${GENERIC_TF_SOURCES}
     x86_64/floatdidf.c
     x86_64/floatdisf.c
     x86_64/floatdixf.c