Mine

if x86_64-pc-linux-gnu-g++ -DHAVE_CONFIG_H -I. -I. -I.  -I/usr/include/SDL -D_GNU_SOURCE=1 -D_REENTRANT   -finline-limit=300   -floop-optimize2 -fomit-frame-pointer -ftracer -maccumulate-outgoing-args -march=k8 -msse3 -O2 -pipe -MT MovieTexture.o -MD -MP -MF ".deps/MovieTexture.Tpo" \
          -c -o MovieTexture.o `test -f 'arch/MovieTexture/MovieTexture.cpp' || echo './'`arch/MovieTexture/MovieTexture.cpp; \
        then mv -f ".deps/MovieTexture.Tpo" ".deps/MovieTexture.Po"; \
        else rm -f ".deps/MovieTexture.Tpo"; exit 1; \
        fi
arch/InputHandler/InputHandler_SDL.cpp:126: error: `int SDL_EventMask' redeclared as different kind of symbol
/usr/include/SDL/SDL_events.h:108: error: previous declaration of `typedef enum SDL_EventMask SDL_EventMask'
arch/InputHandler/InputHandler_SDL.cpp:126: error: declaration of `int SDL_EventMask'
/usr/include/SDL/SDL_events.h:108: error: conflicts with previous declaration `typedef enum SDL_EventMask SDL_EventMask'
arch/InputHandler/InputHandler_SDL.cpp: In constructor `InputHandler_SDL::InputHandler_SDL()':
arch/InputHandler/InputHandler_SDL.cpp:176: error: expected unqualified-id before '|=' token
arch/InputHandler/InputHandler_SDL.cpp: In member function `virtual void InputHandler_SDL::Update(float)':
arch/InputHandler/InputHandler_SDL.cpp:195: error: expected primary-expression before ')' token
make[2]: *** [InputHandler_SDL.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[2]: Leaving directory `/var/tmp/portage/stepmania-3.9/work/StepMania-3.9-src/src'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/var/tmp/portage/stepmania-3.9/work/StepMania-3.9-src/src'
make: *** [all-recursive] Error 1

!!! ERROR: games-arcade/stepmania-3.9 failed.
Call stack:
  ebuild.sh, line 1545:   Called dyn_compile
  ebuild.sh, line 940:   Called src_compile
  stepmania-3.9.ebuild, line 53:   Called die

!!! Make failed
!!! If you need support, post the topmost build error, and the call stack if relevant.