Thanks.  Yes, this was because I misunderstood how memory is allocated for the argv[] array.

Now fixed the repository.

On 4.1, when trying to run a batch file from a recipe, and that batch file has a space in its path, strange command line corruption appears. The problem did not exist in 3.82.

I'm building make from sources on Windows with MSVC. I rebuilt in debug and ran the code through a debugger.

It turns out that the problem is in file sub_proc.c, in function process_begin, at line 725 (in 4.1 and current git head). The code wants to free argv[0] and replace it with something else. However all strings in argv are in a single memory block, so freeing argv[0] also frees subsequent argv[n] strings, and the memory doesn't always hold the argument content until they are used.