Disable some image comparison tests on architectures such as i686
where intermediate floating-point operations are done with 80-bit long
doubles, and typically later rounded to 64-bit doubles.  This double
rounding causes small differences in the resulting pixel values
compared with other architectures, causing the image comparisons to
fail.

Patch by Mark H Weaver <mhw@netris.org>.

diff -ru libgd-2.2.3.orig/tests/gdimagecopyresampled/basic_alpha.c libgd-2.2.3/tests/gdimagecopyresampled/basic_alpha.c
--- libgd-2.2.3.orig/tests/gdimagecopyresampled/basic_alpha.c	2016-07-21 04:06:42.000000000 -0400
+++ libgd-2.2.3/tests/gdimagecopyresampled/basic_alpha.c	2016-07-29 13:50:56.214877446 -0400
@@ -1,5 +1,6 @@
 /* Testing basic gdImageCopyResampled() functionality with alpha channel */
 
+#include <float.h>
 #include "gd.h"
 #include "gdtest.h"
 
@@ -33,7 +34,8 @@
 	gdImageCopyResampled(copy, im, 0,0, 0,0, 200,200, 400,300);
 	gdImageDestroy(im);
 
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<div class='content'><div id='summary'>2.3.orig/tests/gdimagerotate/bug00067.c libgd-2.2.3/tests/gdimagerotate/bug00067.c
--- libgd-2.2.3.orig/tests/gdimagerotate/bug00067.c	2016-06-18 05:42:16.000000000 -0400
+++ libgd-2.2.3/tests/gdimagerotate/bug00067.c	2016-07-29 13:50:07.566271765 -0400
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <float.h>
 #include "gd.h"
 
 #include "gdtest.h"
@@ -43,7 +44,7 @@
 
 		sprintf(filename, "bug00067_%03d_exp.png", angle);
 		path = gdTestFilePath2("gdimagerotate", filename);
-		if (!gdAssertImageEqualsToFile(path, exp)) {
+		if (FLT_EVAL_METHOD != 2 && !gdAssertImageEqualsToFile(path, exp)) {
 			gdTestErrorMsg("comparing rotated image to %s failed.\n", path);
 			error += 1;
 		}