[llvm] [openmp] [Offload] Remove standalone build in favor of 'runtimes' (PR #162904)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> Oh, sorry, just noticed double `/bin`. Without `/bin`, CMake passes and then build fails over trying to create files in `/usr`:
> 
> ```
> FAILED: [code=1] /usr/lib/llvm/22/bin/offload-tblgen 
> : && /usr/lib/ccache/bin/aarch64-unknown-linux-gnu-clang++ -O2 -pipe -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wno-pass-failed -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Wl,-O1 -Wl,--as-needed -Wl,-z,pack-relative-relocs    -Wl,-rpath-link,/usr/lib/llvm/22/lib64  -Wl,--gc-sections offload/tools/offload-tblgen/CMakeFiles/offload-tblgen.dir/APIGen.cpp.o offload/tools/offload-tblgen/CMakeFiles/offload-tblgen.dir/DocGen.cpp.o offload/tools/offload-tblgen/CMakeFiles/offload-tblgen.dir/EntryPointGen.cpp.o offload/tools/offload-tblgen/CMakeFiles/offload-tblgen.dir/MiscGen.cpp.o offload/tools/offload-tblgen/CMakeFiles/offload-tblgen.dir/offload-tblgen.cpp.o offload/tools/offload-tblgen/CMakeFiles/offload-tblgen.dir/PrintGen.cpp.o -o /usr/lib/llvm/22/bin/offload-tblgen  -Wl,-rpath,"\$ORIGIN/../lib64:/usr/lib/llvm/22/lib64"  /usr/lib/llvm/22/lib64/libLLVMSupport.a  /usr/lib/llvm/22/lib64/libLLVMTableGen.a  /usr/lib/llvm/22/lib64/libLLVMSupport.a  -lrt  -ldl  -lm  /usr/lib64/libz3.so  /usr/lib64/libz.so  /usr/lib64/libzstd.so  /usr/lib/llvm/22/lib64/libLLVMDemangle.a && :
> /usr/bin/aarch64-unknown-linux-gnu-ld.bfd: cannot open output file /usr/lib/llvm/22/bin/offload-tblgen: Permission denied
> aarch64-unknown-linux-gnu-clang++: error: linker command failed with exit code 1 (use -v to see invocation)
> ninja: build stopped: subcommand failed.
> ```

That's weird, I at least got that far when I tried it. I guess it's not able to write the file for some reason?

https://github.com/llvm/llvm-project/pull/162904