(#199) Enable -Wswitch flag for gcc

CMakeLists.txt

@@ -100,6 +100,7 @@ if(("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" ST
      -Wshadow \
      -Wstrict-prototypes \
      -Wwrite-strings \
+     -Wswitch \
      -fno-common \
      -pedantic \
      -std=c11 \

src/game/level/solid.c

@@ -24,7 +24,5 @@ void solid_touches_rect_sides(solid_ref_t solid,
     case SOLID_PLAYER:
         player_touches_rect_sides((player_t *) solid.ptr, object, sides);
         break;
-
-    default: {}
     }
 }