StdPcmDir named the directory by target, march and toolchain, then
grew a case per target for the rest: the wasm flags, and with the first
fix for #43 the mingw prefix. Every other flag BuildStdPcm passes went
unkeyed, so configurations that differed only there took turns
rebuilding one std PCM in place, under the PCMs built against it: a
project with -mtune=generic against project.cpp's -mtune=native on every
run, or two sysroots for one target. And the mingw prefix was keyed only
when there was one, so a build without a prefix landed in the directory
an older release had filled with a CRAFTER_MINGW_DIR=/usr build, and
relinked its objects.
StdPcmFlags is now the one source of the flags BuildStdPcm compiles
with, and StdPcmKey names the directory by target, march and toolchain
followed by a hash of those flags and, for the mingw target, of the
prefix behind its --sysroot. VariantId hashes StdPcmKey in place of the
mingw prefix: units do not notice a std module that moved directories,
so a build has to move with it. Every std PCM directory and build
directory moves once, as after a compiler update; the old ones stay
until `clean` and the cache is cleared by hand.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Jorijn van der Graaf
5d25495621