Reading key presses not working when CTRL key is held down

[soruk42]

My use case is the Matrix Brandy BASIC interpreter, which uses SDL 1.2 (I have a plan to port it, though not sure yet how to deal with the way it writes pixels directly to the framebuffer...). So far most is working, but keypresses involving the CTRL key are not picked up. This is easily demonstrated within Matrix Brandy, by issuing
PRINT GET
and pressing CTRL and any key, you should get that sequence ASCII code back, e.g. CTRL-Q should give 17. When run against the real SDL-1.2.15 this works perfectly, but against sdl12-compat no keypress is seen.

[soruk42]

I've run some comparisons between SDL-1.2.15 and the latest sdl12-compat from github, and it appears when the CTRL key is pressed they keysym.unicode struct member isn't completed.
SDL-1.2.15
'd'
keysym.unicode=100 keysym.sym=100 keysym.mod=0x0
SHIFT+'d'
keysym.unicode=68 keysym.sym=100 keysym.mod=0x1
CTRL+'d'
keysym.unicode=4 keysym.sym=100 keysym.mod=0x40
ALT+'d'
keysym.unicode=100 keysym.sym=100 keysym.mod=0x100

sdl12-compat:
'd'
keysym.unicode=100 keysym.sym=100 keysym.mod=0x0
SHIFT+'d'
keysym.unicode=68 keysym.sym=100 keysym.mod=0x1
CTRL+'d'
keysym.unicode=0 keysym.sym=100 keysym.mod=0x40
ALT+'d'
keysym.unicode=100 keysym.sym=100 keysym.mod=0x100