File pngcheck-fix-signedness-comparsion-issue.patch of Package pngcheck

From 7885b4420fac788679d13ba1f8a28f64ab099a45 Mon Sep 17 00:00:00 2001
From: Rudy Matela <rudy@matela.com.br>
Date: Mon, 19 May 2025 12:01:56 +0200
Subject: [PATCH] fix signedness comparison issue
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Before the change, one gets the following warning on GCC 11:

	cc  -c  -I../zlib -DUSE_ZLIB -pedantic-errors  -Wall -Wextra -Wundef  -O2  -o pngcheck.o pngcheck.c
	pngcheck.c: In function ‘pngcheck’:
	pngcheck.c:1964:36: warning: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Wsign-compare]
	 1964 |                 if (i == Z_OK || i == Z_STREAM_ERROR)
		  |                                    ^~

Z_STREAM_ERROR is defined to be (-2), hence the warning.
cf. https://www.zlib.net/manual.html

Because of this v4.0.0 fails to compile out of the box on systems using recent
GHCs as the former Makefile.unx has `-Werror` active.

This change uses a different variable to store the result of `inflateEnd`.

Since v3.0.3, the variable `i` in main has been changed from signed to
unsigned.  However, inflateEnd returns an `int` not an `unsigned int`, so
reusing the `i` variable as the result doesn't seem proper.
---
 pngcheck.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/pngcheck.c b/pngcheck.c
index 28b5dac..4f5fc42 100644
--- a/pngcheck.c
+++ b/pngcheck.c
@@ -1960,12 +1960,12 @@ FIXME: make sure bit 31 (0x80000000) is 0
                   eod-p);		// ptrdiff_t
                 printf("\n     ");
                 fflush(stdout);
-                i = inflateEnd(&zstrm);	/* we're all done */
-                if (i == Z_OK || i == Z_STREAM_ERROR)
+				int r = inflateEnd(&zstrm);	/* we're all done */
+                if (r == Z_OK || r == Z_STREAM_ERROR)
                   printf(" inflateEnd() returns %s\n     ",
-                    i == Z_OK? "Z_OK" : "Z_STREAM_ERROR");
+                    r == Z_OK? "Z_OK" : "Z_STREAM_ERROR");
                 else
-                  printf(" inflateEnd() returns %d\n     ", i);
+                  printf(" inflateEnd() returns %d\n     ", r);
                 fflush(stdout);
               } else
                 inflateEnd(&zstrm);	/* we're all done */