How to make poppler available inside org.gnu.emacs

I am trying to transition to Emacs (org.gnu.emacs) run via Flatpak.

A hurdle I am running into is that I cannot compile pdf-tools. The log shows

-*- mode: compilation; default-directory: "~/.emacs.d/elpa/pdf-tools-20240429.407/build/server/" -*-
Comint started at Thu Aug 29 10:29:43

/home/tamas/.emacs.d/elpa/pdf-tools-20240429.407/build/server/autobuild -i /home/tamas/.emacs.d/elpa/pdf-tools-20240429.407/
Failed to recognize this system, trying to continue.
---------------------------
 Configuring and compiling 
---------------------------
./configure -q --bindir=/home/tamas/.emacs.d/elpa/pdf-tools-20240429.407/ && make clean && make -s
configure: error: Package requirements (poppler) were not met:

Package 'poppler' not found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables poppler_CFLAGS
and poppler_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.
===========================
     Build failed.  ;o(    
===========================
Note: maybe try the '-d' option.

Comint exited abnormally with code 1 at Thu Aug 29 10:29:44

What is the recommended way to have the poppler headers and libraries available to the container?