ffmpeg v6.0 not building correctly per instructions--configure issue?

I'm having an odd issue I've not encountered until this last week. Configure is saying that nvmpi isn't found. Here's the transcript of my build (docker image) using instructions verbatim from readme:

root@77e3fb2cc250:/# cd /tmp
root@77e3fb2cc250:/tmp# git clone git://source.ffmpeg.org/ffmpeg.git -b release/6.0 --depth=1
Cloning into 'ffmpeg'...
remote: Enumerating objects: 7977, done.
remote: Counting objects: 100% (7977/7977), done.
remote: Compressing objects: 100% (6839/6839), done.
remote: Total 7977 (delta 2105), reused 3674 (delta 841), pack-reused 0
Receiving objects: 100% (7977/7977), 16.76 MiB | 8.62 MiB/s, done.
Resolving deltas: 100% (2105/2105), done.
root@77e3fb2cc250:/tmp# cd ffmpeg
root@77e3fb2cc250:/tmp/ffmpeg# wget -O ffmpeg_nvmpi.patch https://github.com/Keylost/jetson-ffmpeg/raw/master/ffmpeg_patches/ffmpeg6.0_nvmpi.patch
--2023-07-01 10:55:21--  https://github.com/Keylost/jetson-ffmpeg/raw/master/ffmpeg_patches/ffmpeg6.0_nvmpi.patch
Resolving github.com (github.com)... 140.82.113.4
Connecting to github.com (github.com)|140.82.113.4|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://raw.githubusercontent.com/Keylost/jetson-ffmpeg/master/ffmpeg_patches/ffmpeg6.0_nvmpi.patch [following]
--2023-07-01 10:55:21--  https://raw.githubusercontent.com/Keylost/jetson-ffmpeg/master/ffmpeg_patches/ffmpeg6.0_nvmpi.patch
Resolving raw.githubusercontent.com (raw.githubusercontent.com)... 185.199.111.133, 185.199.110.133, 185.199.109.133, ...
Connecting to raw.githubusercontent.com (raw.githubusercontent.com)|185.199.111.133|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 34497 (34K) [text/plain]
Saving to: ‘ffmpeg_nvmpi.patch’

ffmpeg_nvmpi.patch                                                      100%[============================================================================================================================================================================>]  33.69K  --.-KB/s    in 0.003s

2023-07-01 10:55:21 (10.0 MB/s) - ‘ffmpeg_nvmpi.patch’ saved [34497/34497]

root@77e3fb2cc250:/tmp/ffmpeg# git apply ffmpeg_nvmpi.patch
ffmpeg_nvmpi.patch:244: trailing whitespace.

ffmpeg_nvmpi.patch:266: trailing whitespace.

ffmpeg_nvmpi.patch:346: trailing whitespace.

ffmpeg_nvmpi.patch:348: trailing whitespace.

ffmpeg_nvmpi.patch:354: trailing whitespace.

warning: squelched 21 whitespace errors
warning: 26 lines add whitespace errors.
root@77e3fb2cc250:/tmp/ffmpeg# ./configure --enable-nvmpi
ERROR: nvmpi not found using pkg-config

If you think configure made a mistake, make sure you are using the latest
version from Git.  If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.libera.chat.
Include the log file "ffbuild/config.log" produced by configure as this will help
solve the problem.
root@77e3fb2cc250:/tmp/ffmpeg#

The last entry in ffbuild/config.log is:

require_pkg_config nvmpi nvmpi nvmpi.h nvmpi_create_decoder
check_pkg_config nvmpi nvmpi nvmpi.h nvmpi_create_decoder
test_pkg_config nvmpi nvmpi nvmpi.h nvmpi_create_decoder
pkg-config --exists --print-errors nvmpi
Package nvmpi was not found in the pkg-config search path.
Perhaps you should add the directory containing `nvmpi.pc'
to the PKG_CONFIG_PATH environment variable
No package 'nvmpi' found
ERROR: nvmpi not found using pkg-config

Any suggestions what might be the issue or where to look next? I know zero about how configure works.

Keylost / jetson-ffmpeg

ffmpeg v6.0 not building correctly per instructions--configure issue? #13