enable static linked builds

The sqlite loadable extension interface uses libdl, so it is now
omitted from the sqlite3 library and zpm-shell.  The -ldl linker
option isn't needed, and -static is.

There is also a commented out CC to use musl as the C library.  Glibc
doesn't actually support static linking, as it uses libdl for
various name service switch libraries.  The package system doesn't
need to do that, and static linking the binaries reduces dependencies
and eliminates library issues which could make the system unusable.