[projects] Use add_llvm_external_project for implicit projects
This allows disabling implicit projects via the LLVM_TOOL_*_BUILD
variables, similar to how implicit tools can be disabled. They'll still
be enabled by default, since add_llvm_external_project defaults the
LLVM_TOOL_*_BUILD variables to ON for in-tree implciit projects.
Differential Revision: https://reviews.llvm.org/D55105
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348064 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed