hghave: add check for bdist_mpkg

verify: don't init subrepo when missing one is referenced (issue5128) (API) Initializing a subrepo when one doesn't exist is the right thing to do when the parent is being updated, but in few other cases. Unfortunately, there isn't enough context in the subrepo module to distinguish this case. This same issue can be caused with other subrepo aware commands, so there is a general issue here beyond the scope of this fix. A simpler attempt I tried was to add an '_updating' boolean to localrepo, and set/clear it around the call to mergemod.update() in hg.updaterepo(). That mostly worked, but doesn't handle the case where archive will clone the subrepo if it is missing. (I vaguely recall that there may be other commands that will clone if needed like this, but certainly not all do. It seems both handy, and a bit surprising for what should be a read only operation. It might be nice if all commands did this consistently, but we probably need Angel's subrepo caching first, to not make a mess of the working directory.) I originally handled 'Exception' in order to pick up the Aborts raised in subrepo.state(), but this turns out to be unnecessary because that is called once and cached by ctx.sub() when iterating the subrepos. It was suggested in the bug discussion to skip looking at the subrepo links unless -S is specified. I don't really like that idea because missing a subrepo or (less likely, but worse) a corrupt .hgsubstate is a problem of the parent repo when checking out a revision. The -S option seems like a better fit for functionality that would recurse into each subrepo and do a full verification. Ultimately, the default value for 'allowcreate' should probably be flipped, but since the default behavior was to allow creation, this is less risky for now.

setup: detect Python DLL filename from loaded DLL Attempting to build Mercurial from source using MinGW from msys2 on Windows produces a hg.exe that attempts to load e.g. python27.dll. MinGW prefixes its library name with "lib" and adds a period between the major and minor versions. e.g. "libpython2.7.dll." Before this patch, hg.exe files in a MinGW environment would either fail to find a Python DLL or would attempt to load a non-MinGW DLL, which would summarily explode. Either way, hg.exe wouldn't work. This patch improves the code that determines the Python DLL filename to actually use the loaded Python DLL instead of inferring it. Basically we take the handle of the loaded DLL from sys.dllhandle and call a Windows API to try to resolve that handle to a filename.