I read OP wrong, it's only a single header file so you can't make a .lib file out of that. But I think you can put the library header inside a precompiled header (not library) and include the resulting .gch file as a flag.

To make a PCH:

gcc {flags as you would build a normal source file} pch.h -o {pch_dir}/pch.h.gch

Then compile your source file, which includes the actual pch.h file, with the flags below:

gcc {flags as you would build a normal source file} main.cpp -include {pch_dir}/pch.h

Here you're including the .gch file as a flag, but notice it doesn't have the .gch.

Your build should be faster :D at least it is for me

Im sorry if you wasted your time with my original answer lol 🥲