../configure --enable-languages=m2 --disable-plugin

will not build or install m2rte.so but the m2 driver will still attempt
to load it, resulting in failure:

puppydog.mod:

    MODULE PuppyDog;
    
    BEGIN
    
    END PuppyDog.

$ gm2-13 -v puppydog.mod
Driving: gm2-13 -v puppydog.mod -fm2-pathname=- -fm2-pathnameI. -fgen-module-list=- -fscaffold-dynamic -fscaffold-main -flibs=m2cor,m2log,m2pim,m2iso -fplugin=m2rte -l m2cor -l m2log -l m2pim -l m2iso -l stdc++ -l m -l pthread -shared-libgcc
new argc = 18, added_libraries = 7
Using built-in specs.
COLLECT_GCC=gm2-13
COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-suse-linux/13/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-suse-linux
Configured with: ../configure --prefix=/usr --infodir=/usr/share/info --mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64 --enable-languages=c,c++,objc,fortran,obj-c++,ada,go,d,jit,m2 --enable-offload-targets=nvptx-none,amdgcn-amdhsa, --enable-offload-defaulted --without-cuda-driver --enable-host-shared --enable-checking=release --disable-werror --with-gxx-include-dir=/usr/include/c++/13 --with-libstdcxx-zoneinfo=/usr/share/zoneinfo --enable-ssp --disable-libssp --disable-libvtv --enable-cet=auto --disable-libcc1 --enable-plugin --with-bugurl=https://bugs.opensuse.org/ --with-pkgversion='SUSE Linux' --with-slibdir=/lib64 --with-system-zlib --enable-libstdcxx-allocator=new --disable-libstdcxx-pch --enable-libphobos --enable-version-specific-runtime-libs --with-gcc-major-version-only --enable-linker-build-id --enable-linux-futex --enable-gnu-indirect-function --program-suffix=-13 --without-system-libunwind --enable-multilib --with-arch-32=x86-64 --with-tune=generic --with-build-config=bootstrap-lto-lean --enable-link-serialization --build=x86_64-suse-linux --host=x86_64-suse-linux
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.0.1 20230421 (prerelease) [revision f980561c60b0446cc427595198d7f3f4f90e0924] (SUSE Linux) 
COLLECT_GCC_OPTIONS='-v' '-fm2-pathname=-' '-fm2-pathnameI.' '-fgen-module-list=-' '-fscaffold-dynamic' '-fscaffold-main' '-flibs=m2cor,m2log,m2pim,m2iso' '-fplugin=m2rte' '-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' 'a-'
 /usr/lib64/gcc/x86_64-suse-linux/13/cc1gm2 -v -iplugindir=plugin -quiet -dumpdir a- -dumpbase puppydog.mod -dumpbase-ext .mod -mtune=generic -march=x86-64 -version -fm2-pathname=- -fm2-pathnameI. -fgen-module-list=- -fscaffold-dynamic -fscaffold-main -flibs=m2cor,m2log,m2pim,m2iso -fplugin=m2rte -fm2-pathname=- -fm2-pathnameI. puppydog.mod -o /tmp/ccFnCKIC.s
cc1gm2: fatal error: inaccessible plugin file plugin/m2rte.so expanded from short plugin name m2rte: No such file or directory
compilation terminated.