[embedding] MonoVM SONAME doesn't match file name in runtime packs

[lambdageek]

We compile mono as libmonosgen-2.0.so and then rename it to libcoreclr.so in the runtime pack (microsoft.netcore.app.runtime.mono.linux-x64/6.0.0-preview.2.21154.6/runtimes/linux-x64/native/libcoreclr.so).

This means we end up in a situation where linking with "-lcoreclr" works ok:

$ clang -std=c99 -g -o ../../out/native/main main.c -DCORELIB_FULL_PATH=\"/home/parallels/work/monovm-embed-sample/out/native/System.Private.CoreLib.dll\" -L/home/parallels/.nuget/packages/microsoft.netcore.app.runtime.mono.linux-x64/6.0.0-preview.2.21154.6/runtimes/linux-x64/native -lcoreclr -I../../out/native/generated -I../../vendor/mono-headers/include/mono-2.0

but at runtime we get:

$ make run
out/native/main: error while loading shared libraries: libmonosgen-2.0.so: cannot open shared object file: No such file or directory

$ ldd out/native/main 
	linux-vdso.so.1 (0x00007ffd891fc000)
	libmonosgen-2.0.so => not found
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fb250845000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fb250a4a000)

---

Even if we do #34202 (stop using "coreclr" for the monovm name), we should verify that the runtime has the correct SONAME set.

Part of #47763

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[lambdageek]

Updated my embedding sample to work around this issue using patchelf

[steveisok]

@lambdageek I'm assuming this is for 6.0. If not, please adjust accordingly.

[lambdageek]

I think this is post-.net6 work since our mobile scenarios don't use the libcoreclr name.

[akoeplinger]

Duplicate of #34202

[lambdageek]

It's not a duplicate. I'm not asking to rename the shared library (although that is also an acceptable fix). I'm asking to update the mono/mini/CMakeLists.txt to use whatever name we configure when it calls the linker instead of copying it to the final name as a post-build step in mono.proj

[akoeplinger]

@lambdageek that'll be done as part of #34202 once we get rid of the need to rename to libcoreclr, then we can use the correct filename/SONAME.