[tools] Only build lldb-test when needed.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@358533 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index df78037..ee8b65f 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -2,7 +2,11 @@
 add_subdirectory(driver)
 add_subdirectory(intel-features)
 add_subdirectory(lldb-mi)
-add_subdirectory(lldb-test)
+
+# We want lldb-test to be built only when it's needed,
+# i.e. if a target requires it as dependency. The typical
+# example is `check-lldb`. So, we pass EXCLUDE_FROM_ALL here.
+add_subdirectory(lldb-test EXCLUDE_FROM_ALL)
 
 add_lldb_tool_subdirectory(lldb-instr)
 add_lldb_tool_subdirectory(lldb-vscode)