Fix standalone clang builds after fb80b6b2d58.
When clang is built against a prebuilt LLVM, LLVM_SOURCE_DIR is
empty, which due to a cmake quirk caused list lengths to get out
of sync. Add a workaround.
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 8be19b1..e0ceb36 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -1484,9 +1484,14 @@
if (ARG_PATHS)
# Walk ARG_PATHS and collect the current value of the variables in there.
+ # list(APPEND) ignores empty elements exactly if the list is empty,
+ # so start the list with a dummy element and drop it, to make sure that
+ # even empty values make it into the values list.
+ set(ARG_PATH_VALUES "dummy")
foreach(path ${ARG_PATHS})
list(APPEND ARG_PATH_VALUES "${${path}}")
endforeach()
+ list(REMOVE_AT ARG_PATH_VALUES 0)
# Compute paths relative to the directory containing output lit.site.cfg.py.
# Passing ARG_PATH_VALUES as-is to execute_process() makes cmake strip
