Move ExecuteCompilerInvocation to a new library FrontendTool

r110903 introduced a dependency from Frontend to every library that
declared an Action by introducing Action references that previously
resided in the driver in the file ExecuteCompilerInvocation.cpp.
This patch moves ExecuteCompilerInvocation to a new library named
FrontendTool which is intended to bear these dependencies.

llvm-svn: 111873
diff --git a/clang/lib/FrontendTool/CMakeLists.txt b/clang/lib/FrontendTool/CMakeLists.txt
new file mode 100644
index 0000000..26c9fc7
--- /dev/null
+++ b/clang/lib/FrontendTool/CMakeLists.txt
@@ -0,0 +1,5 @@
+set(LLVM_NO_RTTI 1)
+
+add_clang_library(clangFrontendTool
+  ExecuteCompilerInvocation.cpp
+  )