- launch-builder-linux.cc was missing an include for musl
and used function that are not defined in the launchers
- musl caches pids used for raise, breaking sandbox setup
- the mtls contrib plugin won't build, didn't try fixing,
static builds can't really use plugins reliably anyway.
Change-Id: I5ab1664e45ea977e5bcf05e41d825e6014e62146
(cherry picked from commit 022e43aa7f)