See commit 73f5ca3a of Zile: https://git.savannah.gnu.org/cgit/zile.git/commit/
Also see https://savannah.gnu.org/bugs/index.php?66843 "make dist" works, but "make distcheck" fails as Vala-generated C files remain in the out-of-tree build directory. I have not worked out why, but it seems that the rule that should copy the file from the top directory into the sub-directory does not fire. (The Vala compiler is not terribly sympathetic to non-recursive build systems either, so we generate complicated Makefile rules to work around it.) I don't think this is a serious problem, as a) not many people use Vala, and b) not many people use non-recursive build systems; also, c) Vala itself recommends the use of Meson these days. Hence, consider this a placeholder bug for now. If there is demand to fix it, I might be able to find time to look into it further. My own plan, should I need to make another release of Zile (the last release was nearly 4 years ago, and there's little chance of a significant change requiring an update), is to just run "make dist" if it's a minor fix, or to switch back to a recursive build system. (Incidentally, I am using Vala with automake on various other projects, all using single-directory or recursive build systems, and it works fine, including, I discovered last week, using the TAP support in Automake to run Vala's GLib-based test suites. Using Vala & GLib obviates the use of bootstrap+gnulib, which makes builds quite fast enough for my purposes, while still benefitting from the familiarity, power and flexibility of the autotools.) -- https://rrt.sc3d.org