--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/leptonica/src/pngiostub.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,143 @@
+/*====================================================================*
+ -  Copyright (C) 2001 Leptonica.  All rights reserved.
+ -
+ -  Redistribution and use in source and binary forms, with or without
+ -  modification, are permitted provided that the following conditions
+ -  are met:
+ -  1. Redistributions of source code must retain the above copyright
+ -     notice, this list of conditions and the following disclaimer.
+ -  2. Redistributions in binary form must reproduce the above
+ -     copyright notice, this list of conditions and the following
+ -     disclaimer in the documentation and/or other materials
+ -     provided with the distribution.
+ -
+ -  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ -  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ -  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ -  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ANY
+ -  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ -  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ -  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ -  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ -  OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ -  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ -  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *====================================================================*/
+
+/*!
+ * \file pngiostub.c
+ * <pre>
+ *
+ *     Stubs for pngio.c functions
+ * </pre>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config_auto.h>
+#endif  /* HAVE_CONFIG_H */
+
+#include "allheaders.h"
+
+/* --------------------------------------------*/
+#if  !HAVE_LIBPNG   /* defined in environ.h */
+/* --------------------------------------------*/
+
+PIX * pixReadStreamPng(FILE *fp)
+{
+    return (PIX * )ERROR_PTR("function not present", __func__, NULL);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok readHeaderPng(const char *filename, l_int32 *pwidth, l_int32 *pheight,
+                   l_int32 *pbps, l_int32 *pspp, l_int32 *piscmap)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok freadHeaderPng(FILE *fp, l_int32 *pwidth, l_int32 *pheight,
+                    l_int32 *pbps, l_int32 *pspp, l_int32 *piscmap)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok readHeaderMemPng(const l_uint8 *data, size_t size, l_int32 *pwidth,
+                      l_int32 *pheight, l_int32 *pbps, l_int32 *pspp,
+                      l_int32 *piscmap)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_int32 fgetPngResolution(FILE *fp, l_int32 *pxres, l_int32 *pyres)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok isPngInterlaced(const char *filename, l_int32 *pinterlaced)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok fgetPngColormapInfo(FILE *fp, PIXCMAP **pcmap, l_int32 *ptransparency)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok pixWritePng(const char *filename, PIX *pix, l_float32 gamma)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok pixWriteStreamPng(FILE *fp, PIX *pix, l_float32 gamma)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok pixSetZlibCompression(PIX *pix, l_int32 compval)
+
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* ----------------------------------------------------------------------*/
+
+void l_pngSetReadStrip16To8(l_int32 flag)
+{
+    L_ERROR("function not present\n", __func__);
+    return;
+}
+
+/* ----------------------------------------------------------------------*/
+
+PIX * pixReadMemPng(const l_uint8 *filedata, size_t filesize)
+{
+    return (PIX * )ERROR_PTR("function not present", __func__, NULL);
+}
+
+/* ----------------------------------------------------------------------*/
+
+l_ok pixWriteMemPng(l_uint8 **pfiledata, size_t *pfilesize, PIX *pix,
+                    l_float32 gamma)
+{
+    return ERROR_INT("function not present", __func__, 1);
+}
+
+/* --------------------------------------------*/
+#endif  /* !HAVE_LIBPNG */
+/* --------------------------------------------*/