Separate the PNaCl llc into a tool named pnacl-llc (how original!)

tools/CMakeLists.txt

 # NOTE: The tools are organized into groups of four consisting of one large and
 # 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_subdirectory(llvm-config)
 endif()
 
 add_subdirectory(opt)
 add_subdirectory(llvm-as)
 add_subdirectory(llvm-dis)
 add_subdirectory(llvm-mc)
 
 add_subdirectory(llc)
+add_subdirectory(pnacl-llc)
 add_subdirectory(llvm-ranlib)
 add_subdirectory(llvm-ar)
 add_subdirectory(llvm-nm)
 add_subdirectory(llvm-size)
 
 add_subdirectory(llvm-cov)
 add_subdirectory(llvm-prof)
 add_subdirectory(llvm-link)
 add_subdirectory(lli)
 
@@ skipping 30 matching lines @@
   if( CMAKE_SYSTEM_NAME STREQUAL "Linux" )
     add_subdirectory(gold)
   endif()
 endif()
 
 add_llvm_external_project(clang)
 add_llvm_external_project(lld)
 add_llvm_external_project(polly)
 
 set(LLVM_COMMON_DEPENDS ${LLVM_COMMON_DEPENDS} PARENT_SCOPE)