Artaburu released a first beta version of his utility library for the SDCC C compiler. E.g. Mariano the dragon or the recently released Nanako Descend To Hell was written with this library (using the Z88dk compiler as backend) and so it contains a lot of graphics functions, keyboard functions, map functions, etc. You can download it from the Google Code page of the CPCRSlib.
Here are the changes since my last posting:
10/24/2012
cpcrslib for SDCC (beta) released.
05/21/2012
cpcwyzlib for SDCC released.