From a7663fbbcf3b9585bcd97ac71db8a9b30eb76fc7 Mon Sep 17 00:00:00 2001
From: Christophe CURIS <christophe.curis@free.fr>
Date: Sun, 3 Nov 2013 13:08:11 +0100
Subject: [PATCH] wrlib: Add support for v5 of the gif_lib API

As reported by Nicolas (nhs), compilation of wrlib is broken when
switching to gif_lib v5.

The API of gif_lib has known little change to provide thread-safe usage,
so we now detect this in configure and and use the functions as appropriate
in gif.c

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>
Signed-off-by: Carlos R. Mafra <crmafra@gmail.com>
---
 m4/wm_imgfmt_check.m4 | 16 +++++++++++++---
 wrlib/gif.c           | 15 ++++++++++++++-
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/m4/wm_imgfmt_check.m4 b/m4/wm_imgfmt_check.m4
index 1cbb212f..e5f403da 100644
--- a/m4/wm_imgfmt_check.m4
+++ b/m4/wm_imgfmt_check.m4
@@ -19,7 +19,7 @@
 # WM_IMGFMT_CHECK_GIF
 # -------------------
 #
-# Check for GIF file support through 'libgif' or 'libungif'
+# Check for GIF file support through 'libgif', 'libungif' or 'giflib v5'
 # The check depends on variable 'enable_gif' being either:
 #   yes  - detect, fail if not found
 #   no   - do not detect, disable support
@@ -53,7 +53,17 @@ AS_IF([test "x$enable_gif" = "xno"],
               [AC_MSG_ERROR([found $wm_cv_imgfmt_gif but could not find appropriate header - are you missing libgif-dev package?])])
             AS_IF([wm_fn_imgfmt_try_compile "gif_lib.h" "DGifOpenFileName(filename)" ""],
               [wm_cv_imgfmt_gif="$wm_cv_imgfmt_gif version:4"],
-              [AC_MSG_ERROR([found $wm_cv_imgfmt_gif and header, but cannot compile - unsupported version?])])
+              [AC_COMPILE_IFELSE(
+                [AC_LANG_PROGRAM(
+                  [@%:@include <gif_lib.h>
+
+const char *filename = "dummy";],
+                  [  int error_code;
+  DGifOpenFileName(filename, &error_code);] )],
+                [wm_cv_imgfmt_gif="$wm_cv_imgfmt_gif version:5"],
+                [AC_MSG_ERROR([found $wm_cv_imgfmt_gif and header, but cannot compile - unsupported version?])])dnl
+              ]
+            )
             CFLAGS="$wm_save_CFLAGS"])
          ])
     AS_IF([test "x$wm_cv_imgfmt_gif" = "xno"],
@@ -62,7 +72,7 @@ AS_IF([test "x$enable_gif" = "xno"],
         [supported_gfx="$supported_gfx GIF"
          GFXLIBS="$GFXLIBS `echo "$wm_cv_imgfmt_gif" | sed -e 's, *version:.*,,' `"
          AC_DEFINE_UNQUOTED([USE_GIF],
-           [1],
+           [`echo "$wm_cv_imgfmt_gif" | sed -e 's,.*version:,,' `],
            [defined when valid GIF library with header was found])])
     ])
     AM_CONDITIONAL([USE_GIF], [test "x$enable_gif" != "xno"])dnl
diff --git a/wrlib/gif.c b/wrlib/gif.c
index e1b1a732..acbf7da1 100644
--- a/wrlib/gif.c
+++ b/wrlib/gif.c
@@ -48,6 +48,7 @@ RImage *RLoadGIF(const char *file, int index)
 	GifRecordType recType;
 	ColorMapObject *colormap;
 	unsigned char rmap[256], gmap[256], bmap[256];
+	int gif_error;
 
 	if (index < 0)
 		index = 0;
@@ -55,10 +56,17 @@ RImage *RLoadGIF(const char *file, int index)
 	/* default error message */
 	RErrorCode = RERR_BADINDEX;
 
+#if USE_GIF == 4
 	gif = DGifOpenFileName(file);
+#else /* USE_GIF == 5 */
+	gif = DGifOpenFileName(file, &gif_error);
+#endif
 
 	if (!gif) {
-		switch (GifLastError()) {
+#if USE_GIF == 4
+		gif_error = GifLastError();
+#endif
+		switch (gif_error) {
 		case D_GIF_ERR_OPEN_FAILED:
 			RErrorCode = RERR_OPEN;
 			break;
@@ -182,6 +190,7 @@ RImage *RLoadGIF(const char *file, int index)
 	/* yuck! */
 	goto did_not_get_any_errors;
  giferr:
+#if USE_GIF == 4
 	switch (GifLastError()) {
 	case D_GIF_ERR_OPEN_FAILED:
 		RErrorCode = RERR_OPEN;
@@ -193,6 +202,10 @@ RImage *RLoadGIF(const char *file, int index)
 		RErrorCode = RERR_BADIMAGEFILE;
 		break;
 	}
+#else
+	/* With gif_lib v5 there's no way to know what went wrong */
+	RErrorCode = RERR_BADIMAGEFILE;
+#endif
  bye:
 	if (image)
 		RReleaseImage(image);