pmbootstrap aportgen: replace arch=all with native (MR 1965)

Packages like binutils-*, busybox-static-*, gcc-*, grub-efi-*, musl-*
are only needed for the native architecture during cross compilation.
Don't bother with trying to build them for other arches to save time and
to avoid getting stuck frequently at "armv7/binutils-aarch64" etc.

A few people like to use pmbootstrap on aarch64 hosts (e.g. PineBook
Pro), so let's make it available for aarch64 again when we can build
aarch64 packages natively in CI and bpo. (They do get stuck there right
now, because of qemu user emulation.)

Related: https://gitlab.com/postmarketOS/build.postmarketos.org/-/issues/75

pmb/aportgen/binutils.py

@@ -11,15 +11,11 @@ def generate(args, pkgname):
     upstream = pmb.aportgen.core.get_upstream_aport(args, "binutils")
     pmb.helpers.run.user(args, ["cp", "-r", upstream, args.work + "/aportgen"])
 
-    # Architectures to build this package for
-    arches = list(pmb.config.build_device_architectures)
-    arches.remove(arch)
-
     # Rewrite APKBUILD
     fields = {
         "pkgname": pkgname,
         "pkgdesc": "Tools necessary to build programs for " + arch + " targets",
-        "arch": " ".join(arches),
+        "arch": args.arch_native,
         "makedepends_build": "",
         "makedepends_host": "",
         "makedepends": "gettext libtool autoconf automake bison texinfo",