/usr/lib/qt5/bin/qmlplugindump hangs in qemu user emulation

We hit this once a year... here with kde/kwin:

• pmaports!9 (merged)

Then with lomiri, @z3ntu made the following workaround:

• pmaports@514782c3
• pmaports@8689c361

Now the issue happens again, with kde packages compiling for armv7 on bpo (all other arches work fine, and I can't reproduce it outside of builds.sr.ht):

• build.postmarketos.org#74 (closed)
• pmaports!1554 (merged)

zhuowei has made a very good analysis of the problem here, even with a reproducer (we just didn't realize that this is probably the same thing):

• pmaports#190 (comment 141902075)

This issue can be worked around easily with the following. But it's very annoying, so let's try to get this fixed in QEMU eventually.

prepare() {
	default_prepare

	# qmlplugindump fails for armv7+qemu (bpo#74). This is purely for
	# packager knowledge and doesn't affect runtime, so we can disable it.
	if [ "$CARCH" = "armv7" ]; then
		sed -i "s/ecm_find_qmlmodule/# ecm_find_qmlmodule/g" CMakeLists.txt
	fi
}

(There is also qemu#1813398, not sure if related.)