glu: Fix some compiler warnings in libtess

When compiled with the more aggressive compiler warnings such as
-Wshadow and -Wempty-body the libtess code gives a lot more
warnings. This fixes the following issues:

* The 'Swap' macro tries to combine multiple statements into one and
  then consume the trailing semicolon by using if(1){/*...*/}else.
  This gives warnings because the else part ends up with an empty
  statement. It also seems a bit dangerous because if the semicolon
  were missed then it would still be valid syntax but it would just
  ignore the following statement. This patch replaces it with the more
  common idiom do { /*...*/ } while(0).

* 'free' was being used as a local variable name but this shadows the
  global function. This has been renamed to 'free_handle'

* TRUE and FALSE were being unconditionally defined. Although this
  isn't currently a problem it seems better to guard them with #ifndef
  because it's quite common for them to be defined in other headers.

https://bugs.freedesktop.org/show_bug.cgi?id=28845

Signed-off-by: Brian Paul <brianp@vmware.com>

src/libtess/geom.c

@@ -198,7 +198,7 @@ printf("*********************%d\n",RandomInterpolate);
 
 #endif
 
-#define Swap(a,b)	if (1) { GLUvertex *t = a; a = b; b = t; } else
+#define Swap(a,b)	do { GLUvertex *t = a; a = b; b = t; } while (0)
 
 void __gl_edgeIntersect( GLUvertex *o1, GLUvertex *d1,
 			 GLUvertex *o2, GLUvertex *d2,

src/libtess/mesh.c

@@ -38,8 +38,12 @@
 #include "mesh.h"
 #include "memalloc.h"
 
+#ifndef TRUE
 #define TRUE 1
+#endif
+#ifndef FALSE
 #define FALSE 0
+#endif
 
 static GLUvertex *allocVertex()
 {

src/libtess/normal.c

@@ -39,8 +39,12 @@
 #include <math.h>
 #include <assert.h>
 
+#ifndef TRUE
 #define TRUE 1
+#endif
+#ifndef FALSE
 #define FALSE 0
+#endif
 
 #define Dot(u,v)	(u[0]*v[0] + u[1]*v[1] + u[2]*v[2])
 

src/libtess/priorityq-heap.c

@@ -39,8 +39,12 @@
 
 #define INIT_SIZE	32
 
+#ifndef TRUE
 #define TRUE 1
+#endif
+#ifndef FALSE
 #define FALSE 0
+#endif
 
 #ifdef FOR_TRITE_TEST_PROGRAM
 #define LEQ(x,y)	(*pq->leq)(x,y)
@@ -159,7 +163,7 @@ void pqInit( PriorityQ *pq )
 PQhandle pqInsert( PriorityQ *pq, PQkey keyNew )
 {
   long curr;
-  PQhandle free;
+  PQhandle free_handle;
 
   curr = ++ pq->size;
   if( (curr*2) > pq->max ) {
@@ -186,21 +190,21 @@ PQhandle pqInsert( PriorityQ *pq, PQkey keyNew )
   }
 
   if( pq->freeList == 0 ) {
-    free = curr;
+    free_handle = curr;
   } else {
-    free = pq->freeList;
-    pq->freeList = pq->handles[free].node;
+    free_handle = pq->freeList;
+    pq->freeList = pq->handles[free_handle].node;
   }
 
-  pq->nodes[curr].handle = free;
-  pq->handles[free].node = curr;
-  pq->handles[free].key = keyNew;
+  pq->nodes[curr].handle = free_handle;
+  pq->handles[free_handle].node = curr;
+  pq->handles[free_handle].key = keyNew;
 
   if( pq->initialized ) {
     FloatUp( pq, curr );
   }
-  assert(free != LONG_MAX);
-  return free;
+  assert(free_handle != LONG_MAX);
+  return free_handle;
 }
 
 /* really __gl_pqHeapExtractMin */

src/libtess/priorityq.c

@@ -85,7 +85,7 @@ void pqDeletePriorityQ( PriorityQ *pq )
 
 #define LT(x,y)		(! LEQ(y,x))
 #define GT(x,y)		(! LEQ(x,y))
-#define Swap(a,b)	if(1){PQkey *tmp = *a; *a = *b; *b = tmp;}else
+#define Swap(a,b)	do{PQkey *tmp = *a; *a = *b; *b = tmp;}while(0)
 
 /* really __gl_pqSortInit */
 int pqInit( PriorityQ *pq )

src/libtess/render.c

@@ -39,8 +39,12 @@
 #include "tess.h"
 #include "render.h"
 
+#ifndef TRUE
 #define TRUE 1
+#endif
+#ifndef FALSE
 #define FALSE 0
+#endif
 
 /* This structure remembers the information we need about a primitive
  * to be able to render it later, once we have determined which
@@ -143,11 +147,11 @@ static void RenderMaximumFaceGroup( GLUtesselator *tess, GLUface *fOrig )
 
 #define AddToTrail(f,t)	((f)->trail = (t), (t) = (f), (f)->marked = TRUE)
 
-#define FreeTrail(t)	if( 1 ) { \
+#define FreeTrail(t)	do { \
 			  while( (t) != NULL ) { \
 			    (t)->marked = FALSE; t = (t)->trail; \
 			  } \
-			} else /* absorb trailing semicolon */
+			} while(0) /* absorb trailing semicolon */
 
 
 

src/libtess/sweep.c

@@ -46,8 +46,12 @@
 #include "memalloc.h"
 #include "sweep.h"
 
+#ifndef TRUE
 #define TRUE 1
+#endif
+#ifndef FALSE
 #define FALSE 0
+#endif
 
 #ifdef FOR_TRITE_TEST_PROGRAM
 extern void DebugEvent( GLUtesselator *tess );

src/libtess/tess.c

@@ -47,8 +47,12 @@
 #define GLU_TESS_DEFAULT_TOLERANCE 0.0
 #define GLU_TESS_MESH		100112	/* void (*)(GLUmesh *mesh)	    */
 
+#ifndef TRUE
 #define TRUE 1
+#endif
+#ifndef FALSE
 #define FALSE 0
+#endif
 
 /*ARGSUSED*/ static void GLAPIENTRY noBegin( GLenum type ) {}
 /*ARGSUSED*/ static void GLAPIENTRY noEdgeFlag( GLboolean boundaryEdge ) {}