CMake: build llvm-config on Windows.

It was previously not being built on Windows because the cmake file relied
on a sed script to generate a .in file that llvm-config needs.

By using cmake's configure_file function, we can get rid off the sed hack,
and also have this work on Windows.

Differential Revision: http://llvm-reviews.chandlerc.com/D1481

llvm-svn: 189125
diff --git a/llvm/tools/CMakeLists.txt b/llvm/tools/CMakeLists.txt
index 66271a9..8a635a5 100644
--- a/llvm/tools/CMakeLists.txt
+++ b/llvm/tools/CMakeLists.txt
@@ -2,13 +2,7 @@
 # three small executables. This is done to minimize memory load in parallel
 # builds.  Please retain this ordering.
 
-if( NOT WIN32 OR MSYS OR CYGWIN )
-  # We currently require 'sed' to build llvm-config, so don't try to build it
-  # on pure Win32.
-  add_llvm_tool_subdirectory(llvm-config)
-else()
-  ignore_llvm_tool_subdirectory(llvm-config)
-endif()
+add_llvm_tool_subdirectory(llvm-config)
 
 add_llvm_tool_subdirectory(opt)
 add_llvm_tool_subdirectory(llvm-as)