BUILD: On PSP use -O2 to fix compiling with new toolchain

-O2 works, but the updated psp compiler doesn't compile
with -O3. It gives the error
```
graphics/macgui/macwindowmanager.cpp: In member function 'void Graphics::MacWindowManager::passPalette(const byte*, uint)':
graphics/macgui/macwindowmanager.cpp:517:1: error: unrecognizable insn:
 }
 ^
(insn 139 138 140 23 (set (reg:SI 294)
        (if_then_else:SI (ne:CC (reg:CC 67 $fcc0)
                (const_int 0 [0]))
            (reg/v:SI 256 [ di ])
            (reg/v:SI 229 [ di ]))) -1
     (nil))
graphics/macgui/macwindowmanager.cpp:517:1: internal compiler error: in extract_insn, at recog.c:2202
```

0 files changed, 0 insertions, 0 deletions