Can't build third-party form input module

Trying to follow the new instructions to add modules to the Nginx Docker image. The module I need is form input. It depends on the Nginx Development Kit module.

I set this up in the modules/ directory:

# tree ngx_form_input/
ngx_form_input/
├── build-deps
└── source
# cat ngx_form_input/source 
https://github.com/calio/form-input-nginx-module/archive/v0.12.tar.gz
# cat ngx_form_input/build-deps 
libnginx-mod-http-ndk

Then I run:

docker build --build-arg ENABLED_MODULES="ndk ngx_form_input" -t nginx-with-form-input .

It appears to successfully build the development kit (ndk? ngx_devel_kit?), then tries to build the form input module and fails thusly:

adding module in extra/ngxforminput-1.19.6
error: ngx_devel_kit is required to build ngx_form_input; please put it before ngx_form_input.
make: *** [debian/rules:48: config.status.nginx] Error 1
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2
debuild: fatal error at line 1182:
dpkg-buildpackage -us -uc -ui failed
real 10.21
user 7.61
sys 2.10
make: *** [Makefile:149: module-ngxforminput] Error 29
build_module.sh: ERROR: Build failed
The command '/bin/sh -c set -ex     && apt update     && apt install -y --no-install-suggests --no-install-recommends                 patch make wget mercurial devscripts debhelper dpkg-dev                 quilt lsb-release build-essential libxml2-utils xsltproc                 equivs git g++     && hg clone https://hg.nginx.org/pkg-oss/     && cd pkg-oss     && mkdir /tmp/packages     && for module in $ENABLED_MODULES; do         echo "Building $module for nginx-$NGINX_VERSION";         if [ -d /modules/$module ]; then             echo "Building $module from user-supplied sources";             if [ ! -s /modules/$module/source ]; then                 echo "No source file for $module in modules/$module/source, exiting";                 exit 1;             fi;             if [ -f /modules/$module/build-deps ]; then                 echo "Installing $module build dependencies";                 apt update && apt install -y --no-install-suggests --no-install-recommends $(cat /modules/$module/build-deps | xargs);             fi;             if [ -x /modules/$module/prebuild ]; then                 echo "Running prebuild script for $module";                 /modules/$module/prebuild;             fi;             /pkg-oss/build_module.sh -v $NGINX_VERSION -f -y -o /tmp/packages -n $module $(cat /modules/$module/source);         elif make -C /pkg-oss/debian list | grep -P "^$module\s+\d" > /dev/null; then             echo "Building $module from pkg-oss sources";             cd /pkg-oss/debian;             make rules-module-$module BASE_VERSION=$NGINX_VERSION;             mk-build-deps --install --tool="apt-get -o Debug::pkgProblemResolver=yes --no-install-recommends --yes" debuild-module-$module/nginx-$NGINX_VERSION/debian/control;             make module-$module BASE_VERSION=$NGINX_VERSION;             find ../../ -maxdepth 1 -mindepth 1 -type f -name "*.deb" -exec mv -v {} /tmp/packages/ \;;         else             echo "Don't know how to build $module module, exiting";             exit 1;         fi;     done' returned a non-zero code: 1

Unsure if this problem lies with the module I'm trying to build, or if I'm naming things incorrectly, or what. The development kit seems to be named "ndk" on https://hg.nginx.org/pkg-oss, but the Debian package (as one specifies in the build-deps file) is named "libnginx-mod-http-ndk". Would appreciate if someone can help me understand!

Start with the modules/ngx_form_input/source and modules/ngx_form_input/build-deps files, then trace the module loop and pkg-oss/build_module.sh shown in the Docker build command. Verify how the ndk dependency is named and ordered, and consider the build complete when the image builds successfully with both modules enabled.