cmCustomCommand: Track main dependency explicitly

Store the main dependency as the first entry in the dependency list plus
a boolean member indicating its existence.  Note that this slightly
changes existing behavior: the main dependency was previously the last
entry of the dependency list.

1 files changed, 2 insertions, 1 deletions

diff --git a/Source/cmAddCustomCommandCommand.cxx b/Source/cmAddCustomCommandCommand.cxx
index 0798ed466a..831e9c7d59 100644
--- a/Source/cmAddCustomCommandCommand.cxx
+++ b/Source/cmAddCustomCommandCommand.cxx
@@ -335,9 +335,10 @@ bool cmAddCustomCommandCommand(std::vector<std::string> const& args,
   } else if (target.empty()) {
     // Target is empty, use the output.
     cc->SetOutputs(output);
+    cc->SetMainDependency(main_dependency);
     cc->SetDepends(depends);
     cc->SetImplicitDepends(implicit_depends);
-    mf.AddCustomCommandToOutput(main_dependency, std::move(cc));
+    mf.AddCustomCommandToOutput(std::move(cc));
   } else if (!byproducts.empty()) {
     status.SetError("BYPRODUCTS may not be specified with SOURCE signatures");
     return false;