loader: implement package maps #4638

Job	Run time
Build slim tarball	1m 44s
x86_64-linux: with shared libraries	21m 14s
x86_64-darwin: with shared libraries	43m 58s
aarch64-linux: with shared libraries	18m 17s
aarch64-darwin: with shared libraries	21m 19s
	1h 46m 32s

Provide feedback