MS-Windows follow-up to 2013-10-10T01:03:11Z!rgm@gnu.org: support giflib 5.x.

 src/image.c (GIFLIB_MAJOR): Define to 4 if undefined.
 (GIFLIB_MINOR, GIFLIB_RELEASE): Define to zero if undefined.
 (GifErrorString) [GIFLIB_MAJOR >= 5]: Define a function pointer.
 (gif_load): For giflib v5.x and later, display the error message
 produced by giflib when its functions fail.
 (syms_of_image) <Qlibgif_version> [HAVE_NTGUI]: New DEFSYM.

 lisp/term/w32-win.el (dynamic-library-alist): Define separate lists
 of GIF DLLs for versions before and after 5.0.0 of giflib.

Fixes: debbugs:15531

2 files changed, 59 insertions, 11 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index bdf3a9fb09f..40926622090 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,13 @@
+2013-10-10  Eli Zaretskii  <eliz@gnu.org>
+
+        * image.c (GIFLIB_MAJOR): Define to 4 if undefined.
+        (GIFLIB_MINOR, GIFLIB_RELEASE): Define to zero if undefined.
+        (GifErrorString) [GIFLIB_MAJOR >= 5]: Define a function pointer.
+        (gif_load): For giflib v5.x and later, display the error message
+        produced by giflib when its functions fail.
+        (syms_of_image) <Qlibgif_version> [HAVE_NTGUI]: New DEFSYM.
+        (Bug#15531)
+
 2013-10-10  Dmitry Antipov  <dmantipov@yandex.ru>
 
         * keyboard.c (last_event_timestamp): Remove.  For X selection and
diff --git a/src/image.c b/src/image.c
index c414f5b91bd..86da6116533 100644
--- a/src/image.c
+++ b/src/image.c
@@ -87,10 +87,11 @@ typedef struct w32_bitmap_record Bitmap_Record;
 #define x_defined_color w32_defined_color
 #define DefaultDepthOfScreen(screen) (one_w32_display_info.n_cbits)
 
-/* Version of libpng that we were compiled with, or -1 if no PNG
-   support was compiled in.  This is tested by w32-win.el to correctly
-   set up the alist used to search for PNG libraries.  */
-Lisp_Object Qlibpng_version;
+/* Versions of libpng and libgif that we were compiled with, or -1 if
+   no PNG/GIF support was compiled in.  This is tested by w32-win.el
+   to correctly set up the alist used to search for the respective
+   image libraries.  */
+Lisp_Object Qlibpng_version, Qlibgif_version;
 #endif /* HAVE_NTGUI */
 
 #ifdef HAVE_NS
@@ -7219,8 +7220,15 @@ gif_image_p (Lisp_Object object)
 
 #endif /* HAVE_NTGUI */
 
+/* Giflib before 5.0 didn't define these macros.  */
 #ifndef GIFLIB_MAJOR
-#define GIFLIB_MAJOR 0
+#define GIFLIB_MAJOR 4
+#endif
+#ifndef GIFLIB_MINOR
+#define GIFLIB_MINOR 0
+#endif
+#ifndef GIFLIB_RELEASE
+#define GIFLIB_RELEASE 0
 #endif
 
 #ifdef WINDOWSNT
@@ -7234,6 +7242,7 @@ DEF_IMGLIB_FN (GifFileType *, DGifOpenFileName, (const char *));
 #else
 DEF_IMGLIB_FN (GifFileType *, DGifOpen, (void *, InputFunc, int *));
 DEF_IMGLIB_FN (GifFileType *, DGifOpenFileName, (const char *, int *));
+DEF_IMGLIB_FN (char *, GifErrorString, (int));
 #endif
 
 static bool
@@ -7248,6 +7257,9 @@ init_gif_functions (void)
   LOAD_IMGLIB_FN (library, DGifSlurp);
   LOAD_IMGLIB_FN (library, DGifOpen);
   LOAD_IMGLIB_FN (library, DGifOpenFileName);
+#if GIFLIB_MAJOR >= 5
+  LOAD_IMGLIB_FN (library, GifErrorString);
+#endif
   return 1;
 }
 
@@ -7257,6 +7269,7 @@ init_gif_functions (void)
 #define fn_DGifSlurp            DGifSlurp
 #define fn_DGifOpen             DGifOpen
 #define fn_DGifOpenFileName     DGifOpenFileName
+#define fn_GifErrorString       GifErrorString
 
 #endif /* WINDOWSNT */
 
@@ -7313,6 +7326,9 @@ gif_load (struct frame *f, struct image *img)
   Lisp_Object specified_data = image_spec_value (img->spec, QCdata, NULL);
   unsigned long bgcolor = 0;
   EMACS_INT idx;
+#if GIFLIB_MAJOR >= 5
+  int gif_err;
+#endif
 
   if (NILP (specified_data))
     {
@@ -7326,14 +7342,20 @@ 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);
           return 0;
         }
+#else
+      gif = fn_DGifOpenFileName (SSDATA (file), &gif_err);
+      if (gif == NULL)
+        {
+          image_error ("Cannot open `%s': %s",
+                       file, build_string (fn_GifErrorString (gif_err)));
+          return 0;
+        }
+#endif
     }
   else
     {
@@ -7351,14 +7373,20 @@ gif_load (struct frame *f, struct image *img)
 
 #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);
           return 0;
         }
+#else
+      gif = fn_DGifOpen (&memsrc, gif_read_from_memory, &gif_err);
+      if (!gif)
+        {
+          image_error ("Cannot open memory source `%s': %s",
+                       img->spec, build_string (fn_GifErrorString (gif_err)));
+          return 0;
+        }
+#endif
     }
 
   /* Before reading entire contents, check the declared image size. */
@@ -9372,6 +9400,16 @@ non-numeric, there is no explicit limit on the size of images.  */);
         make_number (-1)
 #endif
         );
+  DEFSYM (Qlibgif_version, "libgif-version");
+  Fset (Qlibgif_version,
+#ifdef HAVE_GIF
+        make_number (GIFLIB_MAJOR * 10000
+                     + GIFLIB_MINOR * 100
+                     + GIFLIB_RELEASE)
+#else
+        make_number (-1)
+#endif
+        );
 #endif
 
   DEFSYM (Qpbm, "pbm");