Skip compiling C-included files during the build (#1386)

* Update the makefile to skip .inc.c files when building

* Rename all C-included source files to .inc.c

src/code/z_actor.c

@@ -3963,7 +3963,7 @@ s32 func_80035124(Actor* actor, PlayState* play) {
     return ret;
 }
 
-#include "z_cheap_proc.c"
+#include "z_cheap_proc.inc.c"
 
 u8 func_800353E8(PlayState* play) {
     Player* player = GET_PLAYER(play);

src/code/z_camera.c

@@ -33,7 +33,7 @@ s32 Camera_UpdateWater(Camera* camera);
 #define DISTORTION_UNDERWATER_STRONG (1 << 3)
 #define DISTORTION_UNDERWATER_FISHING (1 << 4)
 
-#include "z_camera_data.c"
+#include "z_camera_data.inc.c"
 
 /*===============================================================*/
 

src/code/z_onepointdemo.c

@@ -6,7 +6,7 @@ static s16 sDisableAttention = false;
 static s16 sUnused = -1;
 static s32 sPrevFrameCs1100 = -4096;
 
-#include "z_onepointdemo_data.c"
+#include "z_onepointdemo_data.inc.c"
 
 void OnePointCutscene_AddVecSphToVec3f(Vec3f* dst, Vec3f* src, VecSph* vecSph) {
     Vec3f out;