heatshrink | data compression library for embedded/real-time systems

UPDATE: So the question is as follows: My build setup generates an archive/lib (binary output), which I would like to extract some data from, for compression in my case, but that really is not the point.

My instincts tells me, that since a linker can extract constant data from an archive/lib, It should be possible/easy for me to "dump" the binary "contents" of a symbol contained in an archive/lib to e.g. a file....

So that's my question: How to dump binary contents of a symbol in an archive/lib (in ELF format)?

UPDATE: I am building an application based on lvgl. To allow texts I'm using the online tool provided by the lvgl maintainer to convert TrueType fonts into C-code (const data) which is linked into the application for rendering texts. But the resulting data-set for the fonts is getting too large for my available flash memory, but I have a big chunk of un-used RAM. So, I would like to use heatshrink to compress the data, and un-compress to RAM at runtime.

This requires, that my build setup can extract the binary data, compress it, and link to flash, so that my run-time code can de-compress it.

I guessed, that I could stuff all the generated font-data into a "lib", extract the binary data, compress it, and link as a "blob" into the application.

But I'm failing to extract the data to compress from the library

E.g. my font-data declaration looks as follows: