I just noticed that building DMD~master via
make -f posix.mak BUILD=debug
currently takes 3.2 secs while building it via
make -f posix.mak BUILD=release
takes only 3.0 secs on my Ubuntu 18.04 64-bit machine!
Are there more DMD switches other than `BUILD=release` I need to
activate to produce the fastest possible compiler binary? Apart
for compiling it with LDC, that is.
