https://issues.dlang.org/show_bug.cgi?id=14255
--- Comment #6 from hst...@quickfur.ath.cx --- Got bitten by this today. I have an old version of dmd for bootstrapping purposes in /usr/src/d/install, and git checkout of dmd in /usr/src/d/dmd. This setup used to work fine, except that recently, due to changes in druntime/phobos, they no longer compile with the bootstrap version of dmd. So the solution is to put a dmd.conf in /usr/src/d/install so that the old compiler uses its own version of druntime/phobos, which it can compile. Now /usr/src/d/dmd successfully compiles... except that now it can't link anything, because it can't find the right dmd.conf, so it fails to find the correct version of object.d. Solution: put another dmd.conf in /usr/src/d/dmd so that the new compiler can find the right paths, right? Yes, it works... however, now dmd cannot be recompiled, because when posix.mak is running in /usr/src/d/dmd/src, it tries to invoke HOST_DMD, and the old compiler picks up ./dmd.conf instead of the correct one in /usr/src/d/install. Worse, attempting to remedy this by specifying -conf doesn't work, because posix.mak assumes HOST_DMD contains only the pathname to the host dmd executable; any extra parameters appended to HOST_DMD causes the existence check to fail and it refuses to run. So now I'm stuck. The only way out I can see is to put dmd.conf in /etc or $HOME, but that overrides the system-wide dmd.conf. So this is not workable either. I need a way to tell posix.mak to run HOST_DMD with additional flags. Is there a way to do this?? --