Various packages under minimal-bootstrap explicitly use the musl gcc
wrapper (especially the *-static packages).
In #494106, the desire is to allow these packages to run on a host
platform which may differ from the bootstrap seed platform. That host
platform may be a non-musl platform, and furthermore musl may not even
be available on the desired host architecture.
This change aims to make the packages more generic wrt libc. It is
extracted out of #494106.
By default, stdenv runs configure using --disable-dependency-tracking.
This commit adds the same flag to most manual invocations of autotools
configure scripts in minimal-bootstrap.
However, the flag does not apply to musl & zlib, which come with
handwritten configure scripts. It also does not apply to Python, where
the dependency tracking feature is already disabled in automake config.
