fix various gcc/clang warnings found with -Wall

src/gd.c

@@ -3508,9 +3508,11 @@ static void gdImageAALine (gdImagePtr im, int x1, int y1, int x2, int y2, int co
 		return;
 	} else {
 		double ag;
-		ag = (abs(dy) < abs(dx)) ? cos(atan2(dy, dx)) : sin(atan2(dy, dx));
+		/* Cast the long to an int to avoid compiler warnings about truncation.
+		 * This isn't a problem as computed dy/dx values came from ints above. */
+		ag = fabs(abs((int)dy) < abs((int)dx) ? cos(atan2(dy, dx)) : sin(atan2(dy, dx)));
 		if (ag != 0) {
-			wid = abs(thick / ag);
+			wid = thick / ag;
 		} else {
 			wid = 1;
 		}
@@ -3528,7 +3530,7 @@ static void gdImageAALine (gdImagePtr im, int x1, int y1, int x2, int y2, int co
 		return;
 	}
 
-	if (abs(dx) > abs(dy)) {
+	if (abs((int)dx) > abs((int)dy)) {
 		if (dx < 0) {
 			tmp = x1;
 			x1 = x2;

src/gd_interpolation.c

@@ -2415,8 +2415,8 @@ BGD_DECLARE(int) gdTransformAffineCopy(gdImagePtr dst,
 
 	gdImageGetClip(dst, &c1x, &c1y, &c2x, &c2y);
 
-	end_x = bbox.width  + (int) fabs(bbox.x);
-	end_y = bbox.height + (int) fabs(bbox.y);
+	end_x = bbox.width  + abs(bbox.x);
+	end_y = bbox.height + abs(bbox.y);
 
 	/* Get inverse affine to let us work with destination -> source */
 	gdAffineInvert(inv, affine);
@@ -2518,7 +2518,7 @@ BGD_DECLARE(int) gdTransformAffineBoundingBox(gdRectPtr src, const double affine
 
 BGD_DECLARE(int) gdImageSetInterpolationMethod(gdImagePtr im, gdInterpolationMethod id)
 {
-	if (im == NULL || id < 0 || (uintmax_t)id > GD_METHOD_COUNT) {
+	if (im == NULL || (uintmax_t)id > GD_METHOD_COUNT) {
 		return 0;
 	}
 

src/gdtestft.c

@@ -44,7 +44,7 @@ main (int argc, char *argv[])
 #ifdef JISX0208
 	char *s = "Hello. こんにちは Qyjpqg,";	/* String to draw. */
 #else
-	char *s = "Hello. äöü Qyjpqg,";	/* String to draw. */
+	char *s = "Hello. こんにちは Qyjpqg,";	/* String to draw. */
 #endif
 
 	double sz = 40.;

tests/gdimagecolorreplace/gdimagecolorreplace.c

@@ -51,11 +51,13 @@ static void run_tests(gdImagePtr im, int *error)
 		}														\
 	} while (0)
 
-#define CHECK_PIXEL(x, y, expected) do {						\
+#define CHECK_PIXEL(x, y, expected) \
+	do {														\
+		int pix;												\
 		gdImageSetClip(im, 0, 0, 4, 4);							\
-		c = gdImageGetPixel(im, (x), (y));						\
-		if (gdTestAssert(c == (expected)) != 1) {				\
-			printf("%d is expected, but %d\n", expected, c);	\
+		pix = gdImageGetPixel(im, (x), (y));					\
+		if (gdTestAssert(pix == (expected)) != 1) {				\
+			printf("%d is expected, but %d\n", expected, pix);	\
 			*error = -1;										\
 		}														\
 	} while (0)

tests/gdimagefill/bug00104_1.c

@@ -6,8 +6,8 @@
 int main()
 {
 	gdImagePtr im, tile;
-	int im_white, tile_red, tile_blue;
-	int x, y, error = 0;
+	int tile_red, tile_blue;
+	int error = 0;
 	char path[1024];
 	
 	im = gdImageCreate(200, 150);

tests/gdimagefilter/gdCopyBlurred.c

@@ -23,7 +23,7 @@ save(gdImagePtr im, const char *filename) {
     gdImagePng(im, out);
     fclose(out);
 #else
-    im, filename;
+    (void)im, (void)filename;
 #endif
 }/* save*/
 
@@ -87,8 +87,7 @@ void blurblank(gdImagePtr im, int radius, double sigma) {
 
 void do_test()
 {
-	gdImagePtr im, imref, tmp;
-    gdImagePtr same, same2;
+	gdImagePtr im, imref;
 
 	im = mkwhite(WIDTH, HEIGHT);
     imref = mkwhite(WIDTH, HEIGHT);

tests/gdimagerotate/php_bug_64898.c

@@ -11,7 +11,6 @@ int main()
 	const char *file_im = "gdimagerotate/php_bug_64898.png";
 	const char *file_exp = "gdimagerotate/php_bug_64898_exp.png";
 	FILE *fp;
-	int color;
 
 	sprintf(path, "%s/%s", GDTEST_TOP_DIR, file_im);
 

tests/gdinterpolatedscale/gdTrivialResize.c

@@ -58,8 +58,7 @@ void scaletest(int x, int y, int nx, int ny)
 
 void do_test(int x, int y, int nx, int ny)
 {
-	gdImagePtr im, imref, tmp;
-    gdImagePtr same, same2;
+	gdImagePtr im, imref, same;
 
 	im = mkwhite(x, y);
     imref = mkwhite(x, y);

tests/gdtest/gdtest.c

@@ -77,7 +77,7 @@ void gdTestImageDiff(gdImagePtr buf_a, gdImagePtr buf_b,
 				r1 = gdTrueColorGetRed(c1);
 				r2 = gdTrueColorGetRed(c2);
 				diff_r = abs (r1 - r2);
-				/* diff_r *= 4;  /* emphasize */
+				// diff_r *= 4;  /* emphasize */
 				if (diff_r) {
 					diff_r += gdRedMax/2; /* make sure it's visible */
 				}