diff --git a/source/build/include/clip.h b/source/build/include/clip.h
index 20256653e..d071b8b4b 100644
--- a/source/build/include/clip.h
+++ b/source/build/include/clip.h
@@ -53,8 +53,6 @@ typedef struct
     int32_t maxdist;
 } clipinfo_t;
 
-extern clipinfo_t clipinfo[CM_MAX];
-
 typedef struct
 {
     int16_t numsectors, numwalls;
@@ -62,16 +60,9 @@ typedef struct
     uwalltype *wall;
 } mapinfo_t;
 
-extern mapinfo_t origmapinfo, clipmapinfo;
-
-extern void engineInitClipMaps();
 extern int32_t quickloadboard;
-extern int16_t *sectq;
-extern int16_t pictoidx[MAXTILES];  // maps tile num to clipinfo[] index
-extern int16_t clipspritelist[MAXCLIPNUM];
+extern void engineInitClipMaps();
 extern void engineSetClipMap(mapinfo_t *bak, mapinfo_t *newmap);
-extern int32_t clipsprite_try(uspritetype const * spr, int32_t xmin, int32_t ymin, int32_t xmax, int32_t ymax);
-extern int32_t clipsprite_initindex(int32_t curidx, uspritetype const * curspr, int32_t *clipsectcnt, const vec3_t *vect);
 
 #endif // HAVE_CLIPSHAPE_FEATURE
 typedef struct
@@ -79,11 +70,7 @@ typedef struct
     int32_t x1, y1, x2, y2;
 } linetype;
 
-extern linetype clipit[MAXCLIPNUM];
-
-extern int16_t clipnum;
-extern int32_t clipsectnum, origclipsectnum, clipspritenum;
-extern int16_t clipsectorlist[MAXCLIPSECTORS], origclipsectorlist[MAXCLIPSECTORS];
+extern int16_t clipsectorlist[MAXCLIPSECTORS];
 
 int clipinsidebox(vec2_t *vect, int wallnum, int walldist);
 int clipinsideboxline(int x, int y, int x1, int y1, int x2, int y2, int walldist);
@@ -92,12 +79,12 @@ int sectoradjacent(int sect1, int sect2);
 
 extern int32_t clipmoveboxtracenum;
 
-int32_t clipmove(vec3_t * const pos, int16_t * const sectnum, int32_t xvect, int32_t yvect, int32_t const walldist, int32_t const ceildist,
-    int32_t const flordist, uint32_t const cliptype) ATTRIBUTE((nonnull(1, 2)));
-int32_t clipmovex(vec3_t * const pos, int16_t * const sectnum, int32_t xvect, int32_t yvect, int32_t const walldist, int32_t const ceildist,
-    int32_t const flordist, uint32_t const cliptype, uint8_t const noslidep) ATTRIBUTE((nonnull(1, 2)));
-int32_t pushmove(vec3_t * const vect, int16_t * const sectnum, int32_t const walldist, int32_t const ceildist, int32_t const flordist,
-    uint32_t const cliptype) ATTRIBUTE((nonnull(1, 2)));
+int32_t clipmove(vec3_t *const pos, int16_t *const sectnum, int32_t xvect, int32_t yvect, int32_t const walldist, int32_t const ceildist,
+                 int32_t const flordist, uint32_t const cliptype) ATTRIBUTE((nonnull(1, 2)));
+int32_t clipmovex(vec3_t *const pos, int16_t *const sectnum, int32_t xvect, int32_t yvect, int32_t const walldist, int32_t const ceildist,
+                  int32_t const flordist, uint32_t const cliptype, uint8_t const noslidep) ATTRIBUTE((nonnull(1, 2)));
+int32_t pushmove(vec3_t *const vect, int16_t *const sectnum, int32_t const walldist, int32_t const ceildist, int32_t const flordist,
+                 uint32_t const cliptype) ATTRIBUTE((nonnull(1, 2)));
 
 #ifdef __cplusplus
 }
diff --git a/source/build/src/clip.cpp b/source/build/src/clip.cpp
index 40cf5223c..7f2dfab48 100644
--- a/source/build/src/clip.cpp
+++ b/source/build/src/clip.cpp
@@ -9,14 +9,17 @@
 #include "a.h"
 #include "build.h"
 #include "baselayer.h"
+#include "clip.h"
 #include "engine_priv.h"
 
-int16_t clipnum;
-linetype clipit[MAXCLIPNUM];
-int32_t clipsectnum, origclipsectnum, clipspritenum;
-int16_t clipsectorlist[MAXCLIPSECTORS], origclipsectorlist[MAXCLIPSECTORS];
+static int16_t clipnum;
+static linetype clipit[MAXCLIPNUM];
+static int32_t clipsectnum, origclipsectnum, clipspritenum;
+int16_t clipsectorlist[MAXCLIPSECTORS];
+static int16_t origclipsectorlist[MAXCLIPSECTORS];
+static uint8_t clipsectormap[MAXCLIPSECTORS >> 3];
 #ifdef HAVE_CLIPSHAPE_FEATURE
-int16_t clipspritelist[MAXCLIPNUM];  // sector-like sprite clipping
+static int16_t clipspritelist[MAXCLIPNUM];  // sector-like sprite clipping
 #endif
 static int16_t clipobjectval[MAXCLIPNUM];
 
@@ -41,16 +44,16 @@ void engineSetClipMap(mapinfo_t *bak, mapinfo_t *newmap)
     }
 }
 
-mapinfo_t origmapinfo, clipmapinfo;
+static mapinfo_t origmapinfo, clipmapinfo;
 int32_t quickloadboard=0;
 
-clipinfo_t clipinfo[CM_MAX];
+static clipinfo_t clipinfo[CM_MAX];
 static int32_t numclipmaps;
 
 static int32_t numclipsects;  // number in sectq[]
 static int16_t *sectoidx;
-int16_t *sectq;  // [numsectors]
-int16_t pictoidx[MAXTILES];  // maps tile num to clipinfo[] index
+static int16_t *sectq;  // [numsectors]
+static int16_t pictoidx[MAXTILES];  // maps tile num to clipinfo[] index
 static int16_t *tempictoidx;
 
 static usectortype *loadsector;