Build from source of 1.9.0-beta1 to beta4 broken due to suite-sparse

[fxcoudert]

Pull request #46348 introduced linker option --warn-unresolved-symbols. This is supported by GNU ld, but not by the macOS system linker, so when building from source we error out with:

2023-02-20T09:18:13.6766340Z checking if the linker (ld) is GNU ld... /Applications/Xcode.app/Contents/Developer/usr/bin/make install INSTALL=/private/tmp/julia-20230220-10153-1cp20up/julia-1.9.0-beta4/deps/scratch/SuiteSparse-5.10.1
2023-02-20T09:18:13.6767810Z clang -mmacosx-version-min=13  -Wl,-rpath,/opt/homebrew/Cellar/julia/1.9.0-beta4/lib/julia -Wl,-rpath,/opt/homebrew/opt/curl/lib -Wl,-rpath,/opt/homebrew/opt/mbedtls@2/lib -Wl,-rpath,/opt/homebrew/opt/openblas/lib -Wl,-rpath,/opt/homebrew/opt/gcc/lib/gcc/current -Wl,-rpath,/opt/homebrew/lib -Wl,-rpath,/usr/lib -L/private/tmp/julia-20230220-10153-1cp20up/julia-1.9.0-beta4/deps/scratch/SuiteSparse-5.10.1/lib -Wl,-rpath,'@loader_path/'  -Wl,--warn-unresolved-symbols -dynamiclib -compatibility_version 5 -current_version 5.10.1 -Wl,-install_name -Wl,@rpath/libsuitesparseconfig.5.dylib -shared -undefined dynamic_lookup SuiteSparse_config.o -o /private/tmp/julia-20230220-10153-1cp20up/julia-1.9.0-beta4/deps/scratch/SuiteSparse-5.10.1/lib/libsuitesparseconfig.5.10.1.dylib -lm -rpath /private/tmp/julia-20230220-10153-1cp20up/julia-1.9.0-beta4/deps/scratch/SuiteSparse-5.10.1/lib
2023-02-20T09:18:13.6768700Z ld: unknown option: --warn-unresolved-symbols
2023-02-20T09:18:13.6768940Z clang: error: linker command failed with exit code 1 (use -v to see invocation)

[fxcoudert]

PS: The reason we're building suite-sparse from source is that building against latest suite-sparse (versions 6 or 7) leads to a julia build failure: #47884

[fxcoudert]

On macOS, the flag is not necessary: removing -Wl,--warn-unresolved-symbols from deps/libsuitesparse.mk causes no issue and lets the build proceed to a later unrelated failure (#48057).

[vtjnash]

Error on undef symbol is the default for macOS platform anyways (same for Windows)

[giordano]

-Wl,--warn-unresolved-symbols was added by @Keno in #46348. Any particular reason why that was important for MSAN, or we can just remove it for all platforms?

[Keno]

-Wl,--warn-unresolved-symbols was added by @Keno in #46348. Any particular reason why that was important for MSAN, or we can just remove it for all platforms?

Yes. SuiteSparse tries to force errors on undefined symbols, which msan relies on. -Wl,--warn-unresolved-symbols turns that back into warnings.