[PATCH v2 2/5] w32: add support for recent PNG library version >= 1.5

[Claudio Bley]

The naming scheme of the libpng library on w32 is either libpngXY.dll
or libpngXY-XY.dll where X being the major version, Y the minor
version number, respectively.
---
 lisp/term/w32-win.el | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lisp/term/w32-win.el b/lisp/term/w32-win.el
index b1e7d9b..ff3729d 100644
--- a/lisp/term/w32-win.el
+++ b/lisp/term/w32-win.el
@@ -216,8 +216,15 @@ See the documentation of 
`create-fontset-from-fontset-spec' for the format.")
        ;; the version we were compiled against.  (If we were compiled
        ;; without PNG support, libpng-version's value is -1.)
        (if (>= libpng-version 10400)
-          ;; libpng14-14.dll is libpng 1.4.3 from GTK+
-          '(png "libpng14-14.dll" "libpng14.dll")
+          (let ((major (/ libpng-version 10000))
+                (minor (mod (/ libpng-version 100) 10)))
+            (list 'png
+                  ;; libpngXY.dll is the default name when building
+                  ;; with CMake or from a lpngXYY tarball on w32,
+                  ;; libpngXY-XY.dll is the DLL name when building
+                  ;; with libtool / autotools
+                  (format "libpng%d%d.dll" major minor)
+                  (format "libpng%d%d-%d%d.dll" major minor major minor)))
         '(png "libpng12d.dll" "libpng12.dll" "libpng3.dll" "libpng.dll"
               ;; these are libpng 1.2.8 from GTK+
               "libpng13d.dll" "libpng13.dll"))
-- 
1.8.4.msysgit.0