Hi all,

    I'm trying to build the scratch/igc branch of Emacs in order to see if I
    can help bug hunt, and I'm running into a problem. I apologize if
    this turns out to be a dumb mistake, I don't often build things from
    source.

    I'm following README-IGC's instructions to build the debug version
    of MPS from source to the letter, except I've decided to place
    mps-artifacts in the mps directory, and the mps directory inside my
    emacs source directory, in order to avoid cluttering up my home
    directory. So the commands I'm running are:

        $ # starting in the emacs directory, /home/alexispurslane/Development/scratch/emacs/
        $ git clone https://github.com/Ravenbrook/mps.git
        $ cd mps/code
        $ gcc -O0 -g -DCONFIG_VAR_COOL -c mps.c -o mps-debug.o
        $ ar rvs libmps-debug.a mps-debug.o
        $ cp libmps-debug.a ../mps-artifacts
        $ cd ../..
        $ ./configure CPPFLAGS=-I/home/alexispurslane/Development/scratch/emacs/mps/mps-artifacts LDFLAGS=-I/home/alexispurslane/Development/scratch/emacs/mps/mps-artifacts --with-cairo --with-dbus --with-gif --with-gpm=no --with-harfbuzz --with-jpeg --with-modules --with-native-compilation=aot --with-png --with-rsvg --with-sqlite3 --with-tiff --with-tree-sitter --with-webp --with-x-toolkit=gtk3 --with-xinput2 --with-xpm --with-mps=debug --enable-checking=igc_debug

    When I try to do this, configure reports this error:

        checking for mps.h... yes
        checking for mps_arena_create in -lmps... no
        configure: error: The MPS library libmps is missing

    This seems odd to me not only because I'm providing it with a
    directory that has what it's looking for, but that it appears the
    CPPFLAGS(?) are working, since it can find mps.h, but not the
    LDFLAGS.

    P.S. There's a type in the README-IGC debug build instructions: it
    says `mpc.c' instead of `mps.c' in the GCC command.