bug#16754: unnecessary requirement of X11 for imagemagick in case of cygwin

[Mirek Kaim]

i've just compiled the latest version from repo under cygwin. imagemagick 
installed from cygwin package, with all dependecies - that includes some 
X-libs, but no X server per se. emacs configured --with-w32. all i did was this:

diff --git a/configure.ac b/configure.ac
index 326d528..bc95daa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2236,7 +2236,7 @@ if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes"
fi

HAVE_IMAGEMAGICK=no
-if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes"; then
+#if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes"; then
if test "${with_imagemagick}" != "no"; then
## 6.2.8 is the earliest version known to work, but earlier versions
## might work - let us know if you find one.
@@ -2254,7 +2254,7 @@ if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes"
AC_CHECK_FUNCS(MagickExportImagePixels MagickMergeImageLayers)
fi
fi
-fi
+#fi


HAVE_GTK=no

and it works, checked with image-dired and pdf page scaling. obviously, 
imagemagick is independent from the actual gui used by emacs - as long as there 
is a gui, it makes sense to link with it. shouldn't it be then:

if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes" || test 
"${HAVE_W32}" = "yes"; then

or am i missing something? i'm not too familiar with configure and makefile 
stuff, and i never submitted a patch so i don't have an account, so feel free 
to patch that.