add_custom_{command,target}: Add COMMAND_EXPAND_LISTS option

This option allows lists generated by generator expressions to be expanded.

Closes: #15935

1 files changed, 12 insertions, 1 deletions

diff --git a/Source/cmAddCustomTargetCommand.cxx b/Source/cmAddCustomTargetCommand.cxx
index 56f33b4..0d01493 100644
--- a/Source/cmAddCustomTargetCommand.cxx
+++ b/Source/cmAddCustomTargetCommand.cxx
@@ -47,6 +47,7 @@ bool cmAddCustomTargetCommand::InitialPass(
   std::string working_directory;
   bool verbatim = false;
   bool uses_terminal = false;
+  bool command_expand_lists = false;
   std::string comment_buffer;
   const char* comment = CM_NULLPTR;
   std::vector<std::string> sources;
@@ -90,6 +91,9 @@ bool cmAddCustomTargetCommand::InitialPass(
     } else if (copy == "USES_TERMINAL") {
       doing = doing_nothing;
       uses_terminal = true;
+    } else if (copy == "COMMAND_EXPAND_LISTS") {
+      doing = doing_nothing;
+      command_expand_lists = true;
     } else if (copy == "COMMENT") {
       doing = doing_comment;
     } else if (copy == "COMMAND") {
@@ -221,12 +225,19 @@ bool cmAddCustomTargetCommand::InitialPass(
       "USES_TERMINAL may not be specified without any COMMAND");
     return true;
   }
+  if (commandLines.empty() && command_expand_lists) {
+    this->Makefile->IssueMessage(
+      cmake::FATAL_ERROR,
+      "COMMAND_EXPAND_LISTS may not be specified without any COMMAND");
+    return true;
+  }
 
   // Add the utility target to the makefile.
   bool escapeOldStyle = !verbatim;
   cmTarget* target = this->Makefile->AddUtilityCommand(
     targetName, excludeFromAll, working_directory.c_str(), byproducts, depends,
-    commandLines, escapeOldStyle, comment, uses_terminal);
+    commandLines, escapeOldStyle, comment, uses_terminal,
+    command_expand_lists);
 
   // Add additional user-specified source files to the target.
   target->AddSources(sources);