Change softload_gnu to be off by default
This involves introducing the concept of opt-in jobs, controlled by the ENABLE_JOBS environment variable, analogous to the pre-existing SUPPRESS_JOBS variable. A large bulk of components don't currently build with the GNU tools, due to deficiencies in the shared makefiles and the fact that we don't currently autobuild ELF versions of libraries for them to link against. Having softload_gnu be off by default saves us from having to explicitly disable it in dozens of .gitlab-ci.yml files only to have to come back later to re-enable it once the build infrastructure becomes available.
gnu-default-off in 4 seconds (queued for 2 seconds)1 job for