Qubes Builder hangup

[leopoldmorse]

Trying to roll my own install of 4.1 (running Fedora 31 currently) in the hopes I can at least swap out the previous (probably hardware-related) problems I was having with the readymade 4.0.3 ISO for different ones. (Relevant: trying to install the Archlinux template stuff too, too, because I'll want to fool around with that.) These are the final lines make cubes spits out before terminating:

*** patch ./patch-xen-tools-qubes-vm.patch failed ***
==> ERROR: A failure occurred in build().
    Aborting...
make[2]: *** [/home/sfenn/qubes-builder/qubes-src/builder-archlinux/Makefile.archlinux:121: dist-package] Error 4
make[1]: *** [Makefile.generic:191: packages] Error 1
make: *** [Makefile:227: vmm-xen-vm] Error 1

Am I reading this correctly: Makefile line 227 is throwing an error which causes an error at Makefile.generic line 191, which causes an error at Makefile.archlinux line 121? Or does the causality run in the reverse order? Seems like a problem when we get to vmm-xen-vm the definition of PACKAGE_SET results in PACKAGE being undefined? Or again, is it backwards? Any ideas regarding what's going wrong? Any possible adjustments? Maybe I ought to try building without the Archlinux template, see if that changes things?
For easy reference, I'm including the relevant blocks of code, below. Thanks in advance for any insight.

From Makefile:

226 $(COMPONENTS_NO_TPL_BUILDER:%=%-vm) : %-vm : check-depend
227 @$(call check_branch,$*)
228 @if [ -r $(SRC_DIR)/$*/Makefile.builder ]; then \
229 for DIST in $(DISTS_VM_NO_FLAVOR); do \
230 $(MAKE) --no-print-directory DIST=$$DIST PACKAGE_SET=vm COMPONENT=$* ENV_COMPONENT=$(ENV_$(subst -,_,$*)) -f Makefile.generic all || exit 1; \
231 done; \
232 elif [ -n "`$(MAKE) -n -s -C $(SRC_DIR)/$* rpms-vm 2> /dev/null`" ]; then \
233     for DIST in $(DISTS_VM_NO_FLAVOR); do \
234         MAKE_TARGET="rpms-vm" ./scripts/build $$DIST $* || exit 1; \
235     done; \
236 fi

...and from Makefile.generic:

189 .PHONY: packages
190 packages:
191 @for package in $(PACKAGE_LIST); do\
192 set -o pipefail;\
193 echo "-> Building $(COMPONENT) ($$package) for $(DIST) $(PACKAGE_SET) (logfile: $(BUILD_LOG))";\
194 if [ $(VERBOSE) -eq 0 ]; then\
195 $(MAKE) -f $(THIS_MAKEFILE) PACKAGE=$$package package 3>&1 >>"$(BUILD_LOG)" 2>&1;\
196 BUILD_RETCODE=$$?;\
197 elif [ $(VERBOSE) -eq 1 ]; then\
198 $(MAKE) -s -f $(THIS_MAKEFILE) PACKAGE=$$package package 3>&2 2>&1 | tee -a $(BUILD_LOG);\
199 BUILD_RETCODE=$$?;\
200 else\
201 $(MAKE) -f $(THIS_MAKEFILE) PACKAGE=$$package package 3>&2 2>&1 | tee -a $(BUILD_LOG);\
202 BUILD_RETCODE=$$?;\
203 fi;\
204 if [ $$BUILD_RETCODE -gt 0 ]; then\
205 echo "--> build failed!";\
206 [ $(VERBOSE) -eq 0 ] && tail -n 50 "$(BUILD_LOG)";\
207 exit 1;\
208 fi;\
209 done

...and from /qubes-src/builder-archlinux/Makefile.archlinux

116 # dist-package - compile package (should operate on chroot directory)
117 # TODO: makepkg doesn't seem to honor $http_proxy
118 dist-package:
119 @echo "--> Archlinux dist-package (makefile)"
120 ifndef PACKAGE
121 $(error "PACKAGE need to be set!")
122 endif
123 @echo "  --> Building package in $(DIST_SRC)"
124 sudo $(CHROOT_ENV) chroot "$(CHROOT_DIR)" su user -c 'cd "$(DIST_SRC)" && cp $(PACKAGE)/PKGBUILD* ./ && env http_proxy="$(REPO_PROXY)" makepkg --syncdeps --noconfirm --skipinteg'