Explaining --build --host --target
Ever wondered what specifying build, host and target is all about? In my adventures of creating a compiler for compiling w32 binaries under Linux I ran across these notes which sum up the question better than any other explanation I've seen, so I thought I'd pass them along:
some remarks on specifying --host=<host>, --target=<target> and --build=<build
# kindly provided by Keith Marshall:
# 1) build
# this is *always* the platform on which you are running the build
# process; since we are building on Linux, this is unequivocally going to
# specify `linux', with the canonical form being `i686-pc-linux-gnu'.
# 2) host
# this is a tricky one: it specifies the platform on which whatever we
# are building is going to be run; for the cross-compiler itself, that's
# also `i686-pc-linux-gnu', but when we get to the stage of building the
# runtime support libraries to go with that cross-compiler, they must
# contain code which will run on the `i686-pc-mingw32' host, so the `host'
# specification should change to this, for the `runtime' and `w32api'
# stages of the build.
# 3) target
# this is probably the one which causes the most confusion; it is only
# relevant when building a cross-compiler, and it specifies where the code
# which is built by that cross-compiler itself will ultimately run; it
# should not need to be specified at all, for the `runtime' or `w32api',
# since these are already targetted to `i686-pc-mingw32' by a correct
# `host' specification.