[DEPENDS] Add jemalloc to the depends
This allow to build jemalloc as a static dependency. It also fixes the
missing dependencies for a successful static build on Posix platforms.
Next step is to enable it by default and use it for our release build.
cd depends make build-all
Cross build for all platforms with jemalloc enabled and run the
binaries (requires D6055).
Reviewers: #bitcoin_abc, deadalnix
Reviewed By: #bitcoin_abc, deadalnix
Differential Revision: https://reviews.bitcoinabc.org/D6038