The host-autoconf.make package creates a *-dev.tar.gz package, but the host-autoconf-2.69/bin/auto4mte script install found in it contains a hardcoded path to m4 that results in a build failure for future builds that use the host-autoconf-2.69-arm-*-dev.tar.gz package:
Line 90 of the autom4te in mine has:
my $m4 = $ENV{"M4"} || '/srv/bamboo-home/xml-data/build-dir/29261826/GPEC-EC6-JOB1/platform-ec1c/sysroot-host/bin/m4';

Resulting in a build failure of any package that calls autogen.sh in the extract.post phase:
-------------------------------------
target: host-libfastjson.extract.post
-------------------------------------

pkg_patch_autogen: 'ptxdist-2019.01.0/patches/libfastjson-0.99.8/autogen.sh'

autom4te: need GNU m4 1.4 or later: /srv/bamboo-home/xml-data/build-dir/29261826/GPEC-EC6-JOB1/platform-ec1c/sysroot-host/bin/m4
aclocal: error: echo failed with exit status: 1
/usr/local/lib/ptxdist-2019.01.0/rules/post/ptxd_make_world_extract.make:38: recipe for target '/srv/gpec-build/rootfs/platform-ec1c/state/host-libfastjson.extract.post' failed
make: *** [/srv/gpec-build/rootfs/platform-ec1c/state/host-libfastjson.extract.post] Error 1

-Jon