[builtins] Build x86_64 with GENERIC_TF_SOURCES

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@358706 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/builtins/CMakeLists.txt b/lib/builtins/CMakeLists.txt
index ee828aa..d0bd07b 100644
--- a/lib/builtins/CMakeLists.txt
+++ b/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