bug#15531: Emacs configure fails with gif 5.0

[Barry Fishman <barry_fishman@acm.org>]

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Package: emacs
Version: 24.3.50

The configure script fails to recognize the gif_lib.h header file for
gif 5.0 and so prints an error that git support can not be found.

The gif_lib.h header file has been reorganized for gif 5.0.  There is no
longer a EGifPutExtensionLast function.  However there is a new
GifMakeMapObject I used in my patch.  A better way would probably be to
look at the new GIFLIB_MAJOR define now in gif_lib.h.

I have included a patch, but I do not have many OS/platforms that I
can check.  I am far from understanding autoconfig, but my attempt at a
fix (git patch) is included below:


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diff --git a/configure.ac b/configure.ac
index 53426b6..0f05d8e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3109,8 +3109,9 @@ elif test "${HAVE_X11}" = "yes" && test "${with_gif}" != "no" \
         || test "${HAVE_W32}" = "yes"; then
   AC_CHECK_HEADER(gif_lib.h,
 # EGifPutExtensionLast only exists from version libungif-4.1.0b1.
-# Earlier versions can crash Emacs.
-    [AC_CHECK_LIB(gif, EGifPutExtensionLast, HAVE_GIF=yes, HAVE_GIF=maybe)])
+# Earlier versions can crash Emacs, but version 5.0 removes EGifPutExtensionLast.
+    [AC_CHECK_LIB(gif, GifMakeMapObject, HAVE_GIF=yes,
+        [AC_CHECK_LIB(gif, EGifPutExtensionLast, HAVE_GIF=yes, HAVE_GIF=maybe)])])
 
   if test "$HAVE_GIF" = yes; then
     LIBGIF=-lgif
diff --git a/src/image.c b/src/image.c
index e429830..c414f5b 100644
--- a/src/image.c
+++ b/src/image.c
@@ -7219,14 +7219,22 @@ gif_image_p (Lisp_Object object)
 
 #endif /* HAVE_NTGUI */
 
+#ifndef GIFLIB_MAJOR
+#define GIFLIB_MAJOR 0
+#endif
 
 #ifdef WINDOWSNT
 
 /* GIF library details.  */
 DEF_IMGLIB_FN (int, DGifCloseFile, (GifFileType *));
 DEF_IMGLIB_FN (int, DGifSlurp, (GifFileType *));
+#if GIFLIB_MAJOR < 5
 DEF_IMGLIB_FN (GifFileType *, DGifOpen, (void *, InputFunc));
 DEF_IMGLIB_FN (GifFileType *, DGifOpenFileName, (const char *));
+#else
+DEF_IMGLIB_FN (GifFileType *, DGifOpen, (void *, InputFunc, int *));
+DEF_IMGLIB_FN (GifFileType *, DGifOpenFileName, (const char *, int *));
+#endif
 
 static bool
 init_gif_functions (void)
@@ -7316,7 +7324,11 @@ gif_load (struct frame *f, struct image *img)
 	}
 
       /* Open the GIF file.  */
+#if GIFLIB_MAJOR < 5
       gif = fn_DGifOpenFileName (SSDATA (file));
+#else
+      gif = fn_DGifOpenFileName (SSDATA (file), NULL);
+#endif
       if (gif == NULL)
 	{
 	  image_error ("Cannot open `%s'", file, Qnil);
@@ -7337,7 +7349,11 @@ gif_load (struct frame *f, struct image *img)
       memsrc.len = SBYTES (specified_data);
       memsrc.index = 0;
 
+#if GIFLIB_MAJOR < 5
       gif = fn_DGifOpen (&memsrc, gif_read_from_memory);
+#else
+      gif = fn_DGifOpen (&memsrc, gif_read_from_memory, NULL);
+#endif
       if (!gif)
 	{
 	  image_error ("Cannot open memory source `%s'", img->spec, Qnil);

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-- 
Barry Fishman