diff --git a/src/nodebuild.cpp b/src/nodebuild.cpp
index 081b42f3e..210f0f3de 100644
--- a/src/nodebuild.cpp
+++ b/src/nodebuild.cpp
@@ -937,10 +937,13 @@ void FNodeBuilder::SetNodeFromSeg (node_t &node, const FPrivSeg *pseg) const
 
 DWORD FNodeBuilder::SplitSeg (DWORD segnum, int splitvert, int v1InFront)
 {
+	double dx, dy;
 	FPrivSeg newseg;
 	int newnum = (int)Segs.Size();
 
 	newseg = Segs[segnum];
+	dx = double(Vertices[splitvert].x - Vertices[newseg.v1].x);
+	dy = double(Vertices[splitvert].y - Vertices[newseg.v1].y);
 	if (v1InFront > 0)
 	{
 		newseg.v1 = splitvert;
@@ -1126,7 +1129,8 @@ int ClassifyLineBackpatchC (node_t &node, const FSimpleVert *v1, const FSimpleVe
 	long pagesize = sysconf(_SC_PAGESIZE);
 	char *callerpage = (char *)((intptr_t)calleroffset & ~(pagesize - 1));
 	size_t protectlen = (intptr_t)calleroffset + sizeof(void*) - (intptr_t)callerpage;
-	if (!mprotect(callerpage, protectlen, PROT_READ|PROT_WRITE|PROT_EXEC))
+	int ptect;
+	if (!(ptect = mprotect(callerpage, protectlen, PROT_READ|PROT_WRITE|PROT_EXEC)))
 #endif
 	{
 		*calleroffset = diff;
diff --git a/src/nodebuild_extract.cpp b/src/nodebuild_extract.cpp
index 04660f6d0..c0f769873 100644
--- a/src/nodebuild_extract.cpp
+++ b/src/nodebuild_extract.cpp
@@ -317,6 +317,7 @@ int FNodeBuilder::CloseSubsector (TArray<glseg_t> &segs, int subsector, vertex_t
 		{
 			angle_t bestdiff = ANGLE_MAX;
 			FPrivSeg *bestseg = NULL;
+			DWORD bestj = DWORD_MAX;
 			j = first;
 			do
 			{
@@ -327,12 +328,14 @@ int FNodeBuilder::CloseSubsector (TArray<glseg_t> &segs, int subsector, vertex_t
 				{
 					bestdiff = diff;
 					bestseg = seg;
+					bestj = j;
 					break;
 				}
 				if (diff < bestdiff && diff > 0)
 				{
 					bestdiff = diff;
 					bestseg = seg;
+					bestj = j;
 				}
 			}
 			while (++j < max);
diff --git a/src/nodebuild_gl.cpp b/src/nodebuild_gl.cpp
index 8853a7eab..d029e7f69 100644
--- a/src/nodebuild_gl.cpp
+++ b/src/nodebuild_gl.cpp
@@ -176,7 +176,7 @@ void FNodeBuilder::AddMinisegs (const node_t &node, DWORD splitseg, DWORD &fset,
 	{
 		if (prev != NULL)
 		{
-			DWORD fseg1, bseg1;
+			DWORD fseg1, bseg1, fseg2, bseg2;
 			DWORD fnseg, bnseg;
 
 			// Minisegs should only be added when they can create valid loops on both the front and
@@ -186,8 +186,8 @@ void FNodeBuilder::AddMinisegs (const node_t &node, DWORD splitseg, DWORD &fset,
 
 			if ((fseg1 = CheckLoopStart (node.dx, node.dy, prev->Info.Vertex, event->Info.Vertex)) != DWORD_MAX &&
 				(bseg1 = CheckLoopStart (-node.dx, -node.dy, event->Info.Vertex, prev->Info.Vertex)) != DWORD_MAX &&
-				(CheckLoopEnd (node.dx, node.dy, event->Info.Vertex)) != DWORD_MAX &&
-				(CheckLoopEnd (-node.dx, -node.dy, prev->Info.Vertex)) != DWORD_MAX)
+				(fseg2 = CheckLoopEnd (node.dx, node.dy, event->Info.Vertex)) != DWORD_MAX &&
+				(bseg2 = CheckLoopEnd (-node.dx, -node.dy, prev->Info.Vertex)) != DWORD_MAX)
 			{
 				// Add miniseg on the front side
 				fnseg = AddMiniseg (prev->Info.Vertex, event->Info.Vertex, DWORD_MAX, fseg1, splitseg);