Using custom RGUI bitmap font

Hi, I’d like to customise the default bitmap font used in RGUI. I’ve found out that the font is in gfx>drivers_font_renderer>bitmap.bmp but now I’m wondering how can I make the changes to take effect when compiling retroarch. I saw that also a bitmap.bin exists which is maybe what the make process take into account, but I cannot figure out what is the step I need to perform over the BMP font after changing the same. Any idea?