Test if meta-mono test image can be a reproducible build

[ajlennon]

[zboszor]

I get a lot of warnings of this kind, they are also in CI:

WARNING: mono-6.12.0.182-r0 do_package_qa: QA Issue: File /usr/lib/mono/4.5/gacutil.exe in package mono-libs-4.5 contains reference to TMPDIR

The problem is that the PDB (debuginfo?) file path is embedded in the DLL and EXE files, and it's the native builddir:

$ strings usr/lib/mono/4.5/gacutil.exe | grep tmp
.../tmp-sicom-glibc/work/x86_64-linux/mono-native/6.12.0.182-r0/mono-6.12.0.182/mcs/class/lib/net_4_x-linux/gacutil.pdb

Possibly part of the problem is that the native build artifacts are used to speed up building the target build via this in mono-base.inc:

do_install:append() {
        install -d ${D}${libdir}/${PN}
        for lib in ${MONOLIBS}; do
            if [ -d "${STAGING_DIR_NATIVE}${libdir}/${PN}/$lib" ]; then
                cp -af --no-preserve=ownership \
                    ${STAGING_DIR_NATIVE}${libdir}/${PN}/$lib ${D}${libdir}/${PN}
            fi
        done
        # AJL - Remove mscorlib.dll.so and mcs.exe.so files copied from mono-native to the mono destination
        find ${D}${libdir}/${PN} -name *.dll.so -o -name *.exe.so | xargs -i rm {}
}

The target build for C projects get the -fdebug-prefix-map=src=dst option so whatever file path ends up in *.o, *.so or executables, the mapping will get corrected to use the correct installation file prefix as on a target system.

mcs has a similar switch:

$ mcs --help
...
   -pathmap:K=V[,Kn=Vn] Sets a mapping for source path names used in generated output
...

We should

1. use a correct target build (maybe the native build may still be used? testing is needed) and
2. patch the build of Mono and any Mono based project's build to use -pathmap:... for compiling EXE/DLL files

[ajlennon]

Sounds good to me