Default to disabling ImageMagick (Bug#33587)

ImageMagick has continuing stability and security problems, suggesting
that 'configure' should disable it by default.  See Glenn Morris's notes
at: https://lists.gnu.org/r/emacs-devel/2018-12/msg00036.html
* INSTALL, etc/NEWS, nt/INSTALL.W64: Mention this.
* configure.ac (imagemagick): Default to off.

4 files changed, 11 insertions, 5 deletions

diff --git a/INSTALL b/INSTALL
index e38635c60b7..b2a06b3d153 100644
--- a/INSTALL
+++ b/INSTALL
@@ -295,7 +295,9 @@ or more of these options:
   --without-gif          for GIF image support
   --without-png          for PNG image support
   --without-rsvg         for SVG image support
-  --without-imagemagick  for Imagemagick support
+
+Although ImageMagick support is disabled by default due to security
+and stability concerns, you can enable it with --with-imagemagick.
 
 Use --without-toolkit-scroll-bars to disable Motif or Xaw3d scroll bars.
 
diff --git a/configure.ac b/configure.ac
index 79fe0c98c6f..d13dddfd9a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -432,7 +432,7 @@ OPTION_DEFAULT_ON([lcms2],[don't compile with Little CMS support])
 OPTION_DEFAULT_ON([libsystemd],[don't compile with libsystemd support])
 OPTION_DEFAULT_OFF([cairo],[compile with Cairo drawing (experimental)])
 OPTION_DEFAULT_ON([xml2],[don't compile with XML parsing support])
-OPTION_DEFAULT_ON([imagemagick],[don't compile with ImageMagick image support])
+OPTION_DEFAULT_OFF([imagemagick],[compile with ImageMagick image support])
 OPTION_DEFAULT_ON([json], [don't compile with native JSON support])
 
 OPTION_DEFAULT_ON([xft],[don't use XFT for anti aliased fonts])
diff --git a/etc/NEWS b/etc/NEWS
index fa9ca8603de..f7ee9a9dfe4 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -37,6 +37,10 @@ functions 'json-serialize', 'json-insert', 'json-parse-string', and
 'json-parse-buffer' are typically much faster than their Lisp
 counterparts from json.el.
 
+** Emacs no longer defaults to using ImageMagick to display images,
+due to security and stability concerns.  To override the default, use
+'configure --with-imagemagick'.
+
 ** Several configure options now accept an option-argument 'ifavailable'.
 For example, './configure --with-xpm=ifavailable' now configures Emacs
 to attempt to use libxpm but to continue building even if libxpm is
diff --git a/nt/INSTALL.W64 b/nt/INSTALL.W64
index 994c567c34b..4583aed83bf 100644
--- a/nt/INSTALL.W64
+++ b/nt/INSTALL.W64
@@ -139,10 +139,10 @@ which 'make install' will use - in this example we set it to C:\emacs\emacs-26.
 If a prefix is not specified the files will be put in the standard Unix
 directories located in your C:\msys64 directory, but this is not recommended.
 
-Note also that we need to disable Imagemagick and D-Bus because Emacs
-does not yet support them on Windows.
+Note also that we need to disable D-Bus because Emacs does not yet
+support them on Windows.
 
-  ./configure --prefix=/c/emacs/emacs-26 --without-imagemagick --without-dbus
+  ./configure --prefix=/c/emacs/emacs-26 --without-dbus
 
 ** Run make