[PATCH v2 1/5] w32: define new jpeglib-version var in order to load the correct DLL at runtime

[Claudio Bley <claudio.bley@googlemail.com>]

All jpeglib versions from 7 to 9 are binary incompatible with earlier
ones.
---
 lisp/term/w32-win.el |  4 +++-
 src/image.c          | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lisp/term/w32-win.el b/lisp/term/w32-win.el
index 9690a5a..b1e7d9b 100644
--- a/lisp/term/w32-win.el
+++ b/lisp/term/w32-win.el
@@ -221,8 +221,10 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
 	 '(png "libpng12d.dll" "libpng12.dll" "libpng3.dll" "libpng.dll"
 	       ;; these are libpng 1.2.8 from GTK+
 	       "libpng13d.dll" "libpng13.dll"))
-       '(jpeg "jpeg62.dll" "libjpeg.dll" "jpeg-62.dll" "jpeg.dll")
        '(tiff "libtiff3.dll" "libtiff.dll")
+       (if (> jpeglib-version 0)
+	   (list 'jpeg (format "libjpeg-%d.dll" (/ jpeglib-version 10)))
+	 '(jpeg "jpeg62.dll" "libjpeg.dll" "jpeg-62.dll" "jpeg.dll"))
        ;; Versions of giflib 5.0.0 and later changed signatures of
        ;; several functions used by Emacs, which makes those versions
        ;; incompatible with previous ones.  We select the correct
diff --git a/src/image.c b/src/image.c
index 6691cfc..dea3d35 100644
--- a/src/image.c
+++ b/src/image.c
@@ -92,6 +92,12 @@ typedef struct w32_bitmap_record Bitmap_Record;
    to correctly set up the alist used to search for the respective
    image libraries.  */
 Lisp_Object Qlibpng_version, Qlibgif_version;
+
+/* Version of jpeglib that we were compiled with, or -1 if no JPEG
+   support was compiled in.  This is tested by w32-win.el to correctly
+   set up the alist used to search for JPEG libraries.  */
+Lisp_Object Qjpeglib_version;
+
 #endif /* HAVE_NTGUI */
 
 #ifdef HAVE_NS
@@ -9411,6 +9417,14 @@ non-numeric, there is no explicit limit on the size of images.  */);
 #else
 	make_number (-1)
 #endif
+        );
+  DEFSYM (Qjpeglib_version, "jpeglib-version");
+  Fset (Qjpeglib_version,
+#if HAVE_JPEG
+	make_number (JPEG_LIB_VERSION)
+#else
+	make_number (-1)
+#endif
 	);
 #endif
 
-- 
1.8.4.msysgit.0