gdb/head build, --with-python=<path to working python> FAILs @ "no usable python found " ?

with a local/non-distro python 3.8 installed, via pyenv,

	pyenv global
		3.8-dev
	pyenv which python3.8
		/usr/local/pyenv/versions/3.8-dev/bin/python3.8
	python3.8 -V
		Python 3.8.2+
	python3.8 -c "import sys; print('\n'.join(sys.path))"
		/usr/local/pyenv/versions/3.8-dev/lib/python38.zip
		/usr/local/pyenv/versions/3.8-dev/lib/python3.8
		/usr/local/pyenv/versions/3.8-dev/lib/python3.8/lib-dynload
		/usr/local/pyenv/versions/3.8-dev/lib/python3.8/site-packages

building GDB head

	git clone git://sourceware.org/git/binutils-gdb.git
	cd binutils-gdb
	git log | head
		commit 33aa3c10f663b834c9573ede439b2df3c92f0cfe
		Author: Tom Tromey <[email protected]>
		Date:   Wed Mar 25 10:26:38 2020 -0600
		
	    Fix error message in compile-object-load.c
		...

	./configure \
	 --prefix=/usr/local/gdb \
	 --with-python=/usr/local/pyenv/versions/3.8-dev/bin/python3.8

		...
		configure: creating ./config.status
		config.status: creating Makefile

fails @ make, "no usable python found",

	make V=1

		...
		checking whether to use MPFR... auto
		checking for libmpfr... yes
		checking how to link with libmpfr... -lmpfr -lgmp
		checking whether to use python... /usr/local/pyenv/versions/3.8-dev/bin/python3.8
		checking for python... no
		configure: error: no usable python found at /usr/local/pyenv/versions/3.8-dev/bin/python3.8
		make[1]: *** [Makefile:11664: configure-gdb] Error 1
		make[1]: Leaving directory '/usr/local/src/binutils-gdb'
		make: *** [Makefile:854: all] Error 2

In gdb src, the find-python code's a bit challenging to wade through, and possibly (?) outdated -- as I still see multiple references to EOL'd python 2.7x .


IS gdb/head from upstream known to work with python3?

what is the correct config for sufficiently spec'ing a local python install?