diff --git a/src/client.m b/src/Client.m
similarity index 100%
rename from src/client.m
rename to src/Client.m
diff --git a/src/clientextras.mm b/src/clientextras.m
similarity index 100%
rename from src/clientextras.mm
rename to src/clientextras.m
diff --git a/src/clientgame.mm b/src/clientgame.m
similarity index 97%
rename from src/clientgame.mm
rename to src/clientgame.m
index 6a394b5..a01d4fd 100644
--- a/src/clientgame.mm
+++ b/src/clientgame.m
@@ -9,7 +9,7 @@
 int nextmode = 0; // nextmode becomes gamemode after next map load
 VAR(gamemode, 1, 0, 0);
 
-void
+static void
 mode(int n)
 {
 	addmsg(1, 2, SV_GAMEMODE, nextmode = n);
@@ -144,17 +144,17 @@ respawnself()
 	showscores(false);
 }
 
-void
+static void
 arenacount(
-    DynamicEntity *d, int &alive, int &dead, OFString **lastteam, bool &oneteam)
+    DynamicEntity *d, int *alive, int *dead, OFString **lastteam, bool *oneteam)
 {
 	if (d.state != CS_DEAD) {
-		alive++;
+		(*alive)++;
 		if (![*lastteam isEqual:d.team])
-			oneteam = false;
+			*oneteam = false;
 		*lastteam = d.team;
 	} else
-		dead++;
+		(*dead)++;
 }
 
 int arenarespawnwait = 0;
@@ -177,8 +177,8 @@ arenarespawn()
 		for (id player in players)
 			if (player != [OFNull null])
 				arenacount(
-				    player, alive, dead, &lastteam, oneteam);
-		arenacount(player1, alive, dead, &lastteam, oneteam);
+				    player, &alive, &dead, &lastteam, &oneteam);
+		arenacount(player1, &alive, &dead, &lastteam, &oneteam);
 		if (dead > 0 && (alive <= 1 || (m_teammode && oneteam))) {
 			conoutf(
 			    @"arena round is over! next round in 5 seconds...");
@@ -332,7 +332,7 @@ spawnplayer(DynamicEntity *d)
 // movement input code
 
 #define dir(name, v, d, s, os)                                    \
-	void name(bool isdown)                                    \
+	static void name(bool isdown)                             \
 	{                                                         \
 		player1.s = isdown;                               \
 		player1.v = isdown ? d : (player1.os ? -(d) : 0); \
diff --git a/src/clients.mm b/src/clients.m
similarity index 98%
rename from src/clients.mm
rename to src/clients.m
index 995f900..b467568 100644
--- a/src/clients.mm
+++ b/src/clients.m
@@ -197,11 +197,9 @@ addmsg(int rel, int num, int type, ...)
 {
 	if (demoplayback)
 		return;
-	if (num != msgsizelookup(type)) {
-		fatal([OFString
-		    stringWithFormat:@"inconsistant msg size for %d (%d != %d)",
-		    type, num, msgsizelookup(type)]);
-	}
+	if (num != msgsizelookup(type))
+		fatal(@"inconsistant msg size for %d (%d != %d)", type, num,
+		    msgsizelookup(type));
 	if (messages.count == 100) {
 		conoutf(@"command flood protection (type %d)", type);
 		return;
diff --git a/src/clients2c.mm b/src/clients2c.m
similarity index 99%
rename from src/clients2c.mm
rename to src/clients2c.m
index 06327ef..1372d29 100644
--- a/src/clients2c.mm
+++ b/src/clients2c.m
@@ -308,7 +308,7 @@ localservertoclient(uchar *buf, int len)
 			int xs = getint(&p);
 			int ys = getint(&p);
 			int v = getint(&p);
-			block b = { x, y, xs, ys };
+			struct block b = { x, y, xs, ys };
 			switch (type) {
 			case SV_EDITH:
 				editheightxy(v != 0, getint(&p), &b);
diff --git a/src/console.mm b/src/console.m
similarity index 100%
rename from src/console.mm
rename to src/console.m
diff --git a/src/editing.mm b/src/editing.m
similarity index 90%
rename from src/editing.mm
rename to src/editing.m
index 0d7a047..76eced9 100644
--- a/src/editing.mm
+++ b/src/editing.m
@@ -12,12 +12,12 @@ bool editmode = false;
 // invariant: all code assumes that these are kept inside MINBORD distance of
 // the edge of the map
 
-block sel;
+struct block sel;
 
 OF_CONSTRUCTOR()
 {
 	enqueueInit(^{
-		sel = (block) {
+		sel = (struct block) {
 			variable(@"selx", 0, 0, 4096, &sel.x, NULL, false),
 			variable(@"sely", 0, 0, 4096, &sel.y, NULL, false),
 			variable(@"selxs", 0, 0, 4096, &sel.xs, NULL, false),
@@ -34,7 +34,7 @@ bool selset = false;
 		makeundo();                                 \
 		loop(x, sel->xs) loop(y, sel->ys)           \
 		{                                           \
-			sqr *s = S(sel->x + x, sel->y + y); \
+			struct sqr *s = S(sel->x + x, sel->y + y); \
 			b;                                  \
 		}                                           \
 		remip(sel, 0);                              \
@@ -48,7 +48,7 @@ bool dragging = false;
 int lastx, lasty, lasth;
 
 int lasttype = 0, lasttex = 0;
-sqr rtex;
+static struct sqr rtex;
 
 VAR(editing, 0, 0, 1);
 
@@ -121,7 +121,7 @@ noselection()
 void
 selectpos(int x, int y, int xs, int ys)
 {
-	block s = { x, y, xs, ys };
+	struct block s = { x, y, xs, ys };
 	sel = s;
 	selh = 0;
 	correctsel();
@@ -130,7 +130,7 @@ selectpos(int x, int y, int xs, int ys)
 void
 makesel()
 {
-	block s = { min(lastx, cx), min(lasty, cy), abs(lastx - cx) + 1,
+	struct block s = { min(lastx, cx), min(lasty, cy), abs(lastx - cx) + 1,
 		abs(lasty - cy) + 1 };
 	sel = s;
 	selh = max(lasth, ch);
@@ -141,9 +141,9 @@ makesel()
 
 VAR(flrceil, 0, 0, 2);
 
+// finds out z height when cursor points at wall
 float
-sheight(
-    sqr *s, sqr *t, float z) // finds out z height when cursor points at wall
+sheight(struct sqr *s, struct sqr *t, float z)
 {
 	return !flrceil // z-s->floor<s->ceil-z
 	    ? (s->type == FHF ? s->floor - t->vdelta / 4.0f : (float)s->floor)
@@ -165,7 +165,7 @@ cursorupdate() // called every frame from hud
 
 	if (OUTBORD(cx, cy))
 		return;
-	sqr *s = S(cx, cy);
+	struct sqr *s = S(cx, cy);
 
 	// selected wall
 	if (fabs(sheight(s, s, z) - z) > 1) {
@@ -194,7 +194,7 @@ cursorupdate() // called every frame from hud
 		for (int iy = cy - GRIDSIZE; iy <= cy + GRIDSIZE; iy++) {
 			if (OUTBORD(ix, iy))
 				continue;
-			sqr *s = S(ix, iy);
+			struct sqr *s = S(ix, iy);
 			if (SOLID(s))
 				continue;
 			float h1 = sheight(s, s, z);
@@ -207,7 +207,7 @@ cursorupdate() // called every frame from hud
 				linestyle(GRIDW, 0x80, 0xFF, 0x80);
 			else
 				linestyle(GRIDW, 0x80, 0x80, 0x80);
-			block b = { ix, iy, 1, 1 };
+			struct block b = { ix, iy, 1, 1 };
 			box(&b, h1, h2, h3, h4);
 			linestyle(GRID8, 0x40, 0x40, 0xFF);
 			if (!(ix & GRIDM))
@@ -224,7 +224,7 @@ cursorupdate() // called every frame from hud
 	if (!SOLID(s)) {
 		float ih = sheight(s, s, z);
 		linestyle(GRIDS, 0xFF, 0xFF, 0xFF);
-		block b = { cx, cy, 1, 1 };
+		struct block b = { cx, cy, 1, 1 };
 		box(&b, ih, sheight(s, SWS(s, 1, 0, ssize), z),
 		    sheight(s, SWS(s, 1, 1, ssize), z),
 		    sheight(s, SWS(s, 0, 1, ssize), z));
@@ -247,9 +247,9 @@ pruneundos(int maxremain) // bound memory
 {
 	int t = 0;
 	for (ssize_t i = (ssize_t)undos.count - 1; i >= 0; i--) {
-		block *undo = *(block **)[undos itemAtIndex:i];
+		struct block *undo = [undos mutableItemAtIndex:i];
 
-		t += undo->xs * undo->ys * sizeof(sqr);
+		t += undo->xs * undo->ys * sizeof(struct sqr);
 		if (t > maxremain) {
 			OFFreeMemory(undo);
 			[undos removeItemAtIndex:i];
@@ -262,9 +262,9 @@ makeundo()
 {
 	if (undos == nil)
 		undos =
-		    [[OFMutableData alloc] initWithItemSize:sizeof(block *)];
+		    [[OFMutableData alloc] initWithItemSize:sizeof(struct block *)];
 
-	block *copy = blockcopy(&sel);
+	struct block *copy = blockcopy(&sel);
 	[undos addItem:&copy];
 	pruneundos(undomegs << 20);
 }
@@ -277,13 +277,13 @@ editundo()
 		conoutf(@"nothing more to undo");
 		return;
 	}
-	block *p = *(block **)undos.lastItem;
+	struct block *p = undos.mutableLastItem;
 	[undos removeLastItem];
 	blockpaste(p);
 	OFFreeMemory(p);
 }
 
-block *copybuf = NULL;
+static struct block *copybuf = NULL;
 
 void
 copy()
@@ -351,7 +351,7 @@ editdrag(bool isDown)
 // strictly triggered locally. They all have very similar structure.
 
 void
-editheightxy(bool isfloor, int amount, const block *sel)
+editheightxy(bool isfloor, int amount, const struct block *sel)
 {
 	loopselxy(
 	    if (isfloor) {
@@ -376,7 +376,7 @@ editheight(int flr, int amount)
 COMMAND(editheight, ARG_2INT)
 
 void
-edittexxy(int type, int t, const block *sel)
+edittexxy(int type, int t, const struct block *sel)
 {
 	loopselxy(switch (type) {
 	        case 0:
@@ -419,7 +419,7 @@ replace()
 	EDITSELMP;
 	loop(x, ssize) loop(y, ssize)
 	{
-		sqr *s = S(x, y);
+		struct sqr *s = S(x, y);
 		switch (lasttype) {
 		case 0:
 			if (s->ftex == rtex.ftex)
@@ -439,12 +439,12 @@ replace()
 			break;
 		}
 	}
-	block b = { 0, 0, ssize, ssize };
+	struct block b = { 0, 0, ssize, ssize };
 	remip(&b, 0);
 }
 
 void
-edittypexy(int type, const block *sel)
+edittypexy(int type, const struct block *sel)
 {
 	loopselxy(s->type = type);
 }
@@ -485,7 +485,7 @@ corner()
 COMMAND(corner, ARG_NONE)
 
 void
-editequalisexy(bool isfloor, const block *sel)
+editequalisexy(bool isfloor, const struct block *sel)
 {
 	int low = 127, hi = -128;
 	loopselxy({
@@ -515,7 +515,7 @@ equalize(int flr)
 COMMAND(equalize, ARG_1INT)
 
 void
-setvdeltaxy(int delta, const block *sel)
+setvdeltaxy(int delta, const struct block *sel)
 {
 	loopselxy(s->vdelta = max(s->vdelta + delta, 0));
 	remipmore(sel, 0);
@@ -555,9 +555,9 @@ arch(int sidedelta, int _a)
 		sel.xs = MAXARCHVERT;
 	if (sel.ys > MAXARCHVERT)
 		sel.ys = MAXARCHVERT;
-	block *sel_ = &sel;
+	struct block *sel_ = &sel;
 	// Ugly hack to make the macro work.
-	block *sel = sel_;
+	struct block *sel = sel_;
 	loopselxy(s->vdelta = sel->xs > sel->ys
 	        ? (archverts[sel->xs - 1][x] +
 	              (y == 0 || y == sel->ys - 1 ? sidedelta : 0))
@@ -577,9 +577,9 @@ slope(int xd, int yd)
 		off -= yd * sel.ys;
 	sel.xs++;
 	sel.ys++;
-	block *sel_ = &sel;
+	struct block *sel_ = &sel;
 	// Ugly hack to make the macro work.
-	block *sel = sel_;
+	struct block *sel = sel_;
 	loopselxy(s->vdelta = xd * x + yd * y + off);
 	remipmore(sel, 0);
 }
@@ -612,9 +612,9 @@ void
 edittag(int tag)
 {
 	EDITSELMP;
-	block *sel_ = &sel;
+	struct block *sel_ = &sel;
 	// Ugly hack to make the macro work.
-	block *sel = sel_;
+	struct block *sel = sel_;
 	loopselxy(s->tag = tag);
 }
 
diff --git a/src/entities.mm b/src/entities.m
similarity index 95%
rename from src/entities.mm
rename to src/entities.m
index 08c9c8e..8452b24 100644
--- a/src/entities.mm
+++ b/src/entities.m
@@ -29,9 +29,9 @@ initEntities()
 	ents = [[OFMutableArray alloc] init];
 }
 
-void
-renderent(Entity *e, OFString *mdlname, float z, float yaw, int frame = 0,
-    int numf = 1, int basetime = 0, float speed = 10.0f)
+static void
+renderent(Entity *e, OFString *mdlname, float z, float yaw, int frame/* = 0*/,
+    int numf/* = 1*/, int basetime/* = 0*/, float speed/* = 10.0f*/)
 {
 	rendermodel(mdlname, frame, numf, 0, 1.1f,
 	    OFMakeVector3D(e.x, z + S(e.x, e.y)->floor, e.y), yaw, 0, false,
@@ -67,7 +67,7 @@ renderentities()
 				    (float)(1 +
 				        sin(lastmillis / 100.0 + e.x + e.y) /
 				            20),
-				    lastmillis / 10.0f);
+				    lastmillis / 10.0f, 0,1,0,10.0f);
 			} else {
 				switch (e.attr2) {
 				case 1:
@@ -84,7 +84,8 @@ renderentities()
 					            e.y) /
 					            20),
 					    lastmillis /
-					        (e.attr2 ? 1.0f : 10.0f));
+					        (e.attr2 ? 1.0f : 10.0f),
+						0, 1, 0, 10.0f);
 					break;
 
 				case 4:
@@ -136,12 +137,12 @@ baseammo(int gun)
 static int
 radditem(int i, int v)
 {
-	itemstat &is = itemstats[ents[i].type - I_SHELLS];
+	struct itemstat *is = &itemstats[ents[i].type - I_SHELLS];
 	ents[i].spawned = false;
-	v += is.add;
-	if (v > is.max)
-		v = is.max;
-	playsoundc(is.sound);
+	v += is->add;
+	if (v > is->max)
+		v = is->max;
+	playsoundc(is->sound);
 	return v;
 }
 
diff --git a/src/menus.mm b/src/menus.m
similarity index 100%
rename from src/menus.mm
rename to src/menus.m
diff --git a/src/meson.build b/src/meson.build
index fd8066a..1911c38 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -21,17 +21,17 @@ executable('client',
     'ServerEntity.m',
     'ServerInfo.m',
     'Variable.m',
-    'clients.mm',
-    'clientextras.mm',
-    'clientgame.mm',
-    'clients2c.mm',
+    'clients.m',
+    'clientextras.m',
+    'clientgame.m',
+    'clients2c.m',
     'commands.mm',
-    'console.mm',
-    'editing.mm',
-    'entities.mm',
+    'console.m',
+    'editing.m',
+    'entities.m',
     'init.mm',
-    'menus.mm',
-    'monster.mm',
+    'menus.m',
+    'monster.m',
     'physics.mm',
     'rendercubes.mm',
     'renderextras.mm',
diff --git a/src/monster.mm b/src/monster.m
similarity index 97%
rename from src/monster.mm
rename to src/monster.m
index 12d6261..63191e4 100644
--- a/src/monster.mm
+++ b/src/monster.m
@@ -63,7 +63,7 @@ basicmonster(int type, int yaw, int state, int trigger, int move)
 		type = 0;
 	}
 	DynamicEntity *m = newdynent();
-	monstertype *t = &monstertypes[(m.mtype = type)];
+	struct monstertype *t = &monstertypes[(m.mtype = type)];
 	m.eyeheight = 2.0f;
 	m.aboveeye = 1.9f;
 	m.radius *= t->bscale / 10.0f;
@@ -138,7 +138,7 @@ monsterclear()
 
 // height-correct line of sight for monster shooting/seeing
 bool
-los(float lx, float ly, float lz, float bx, float by, float bz, OFVector3D &v)
+los(float lx, float ly, float lz, float bx, float by, float bz, OFVector3D *v)
 {
 	if (OUTBORD((int)lx, (int)ly) || OUTBORD((int)bx, (int)by))
 		return false;
@@ -151,7 +151,7 @@ los(float lx, float ly, float lz, float bx, float by, float bz, OFVector3D &v)
 	float y = ly;
 	int i = 0;
 	for (;;) {
-		sqr *s = S(fast_f2nat(x), fast_f2nat(y));
+		struct sqr *s = S(fast_f2nat(x), fast_f2nat(y));
 		if (SOLID(s))
 			break;
 		float floor = s->floor;
@@ -163,9 +163,9 @@ los(float lx, float ly, float lz, float bx, float by, float bz, OFVector3D &v)
 		float rz = lz - ((lz - bz) * (i / (float)steps));
 		if (rz < floor || rz > ceil)
 			break;
-		v.x = x;
-		v.y = y;
-		v.z = rz;
+		v->x = x;
+		v->y = y;
+		v->z = rz;
 		x += dx / (float)steps;
 		y += dy / (float)steps;
 		i++;
@@ -174,9 +174,9 @@ los(float lx, float ly, float lz, float bx, float by, float bz, OFVector3D &v)
 }
 
 bool
-enemylos(DynamicEntity *m, OFVector3D &v)
+enemylos(DynamicEntity *m, OFVector3D *v)
 {
-	v = m.o;
+	*v = m.o;
 	return los(
 	    m.o.x, m.o.y, m.o.z, m.enemy.o.x, m.enemy.o.y, m.enemy.o.z, v);
 }
@@ -261,7 +261,7 @@ monsteraction(DynamicEntity *m)
 	              // contact
 	{
 		OFVector3D target;
-		if (editmode || !enemylos(m, target))
+		if (editmode || !enemylos(m, &target))
 			return; // skip running physics
 		normalise(m, enemyyaw);
 		float angle = (float)fabs(enemyyaw - m.yaw);
@@ -295,7 +295,7 @@ monsteraction(DynamicEntity *m)
 		m.targetyaw = enemyyaw;
 		if (m.trigger < lastmillis) {
 			OFVector3D target;
-			if (!enemylos(m, target)) {
+			if (!enemylos(m, &target)) {
 				// no visual contact anymore, let monster get
 				// as close as possible then search for player
 				transition(m, M_HOME, 1, 800, 500);
diff --git a/src/serverbrowser.mm b/src/serverbrowser.mm
index 9bc0dcf..3995f91 100644
--- a/src/serverbrowser.mm
+++ b/src/serverbrowser.mm
@@ -202,7 +202,7 @@ checkpings()
 	}
 }
 
-void
+extern "C" void
 refreshservers()
 {
 	checkresolver();