[MacSDK] Update bockbuild to work around build/staging issue

[MacSDK] Update bockbuild to work around build/staging issue
Commit message: Allow for non-fatal shell execution, and turn “install_name_tool” staging failures to warnings as we find a more permanent solution to AOT dylibs not always having enough field space for the new path (all other dylibs made in the build with the XCode toolchain typically do, as they are built with the “-headerpad_max_install_names” flag.