LLD patch: respect LLD_BUILD_TOOLS=OFF

Without this, cmake will build and install LLD binaries, which are
unwanted, and also cause RPATH failures on some targets.

Author: andrewrk

lld/CMakeLists.txt

@@ -190,7 +190,9 @@ if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
 endif()
 
 add_subdirectory(Common)
-add_subdirectory(tools/lld)
+if(LLD_BUILD_TOOLS)
+  add_subdirectory(tools/lld)
+endif()
 
 if (LLVM_INCLUDE_TESTS)
   add_custom_target(LLDUnitTests)