[evince/gnome-3-28] build: Disable PostScript backend by default

[Germán Poo-Caamaño <gpoo src gnome org>]

commit 3e8ea509ccb9e32717f4856ee7a7e5ff12944e15
Author: Germán Poo-Caamaño <gpoo gnome org>
Date:   Mon Aug 27 15:33:05 2018 -0300

    build: Disable PostScript backend by default
    
    Evince depends on libspectre to render PostScript file, which
    relies on Ghostscript. Ghostscript 9.23 and previous versions
    have a security issue that allow run arbitrary commands in a
    crafted PostScript file, even when it is called with the option
    -dSAFER.
    
    See issue #967

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index 4b54b6a2..222df77b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -573,7 +573,7 @@ AC_ARG_ENABLE(ps,
        [AS_HELP_STRING([--disable-ps],
                        [Disable the PostScript backend])],
        [enable_ps=$enableval],
-       [enable_ps=yes])
+       [enable_ps=no])
 
 if test "x$enable_ps" = "xyes"; then
    if test "x$have_spectre" = "xyes"; then