Make 'configure' work out-of-the-box on Solaris.

* configure.ac: Work even if libgif etc. are missing.  Emacs works
without these libraries even if its default GUI is harmed, so they
are not strictly necessary.  Another possibility would be to
disable X11 if these libraries are missing.  The point is that a
plain 'configure' should not fail on platforms like Solaris 11
where one or more image libraries are not installed by default.

2 files changed, 15 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index 795313685eb..7443e049f61 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2013-12-11  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Make 'configure' work out-of-the-box on Solaris.
+        * configure.ac: Work even if libgif etc. are missing.  Emacs works
+        without these libraries even if its default GUI is harmed, so they
+        are not strictly necessary.  Another possibility would be to
+        disable X11 if these libraries are missing.  The point is that a
+        plain 'configure' should not fail on platforms like Solaris 11
+        where one or more image libraries are not installed by default.
+
 2013-12-11  Glenn Morris  <rgm@gnu.org>
 
         * info/dir: Add octave-mode.
diff --git a/configure.ac b/configure.ac
index 41258fcb7a9..0720b4bf56e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3106,7 +3106,8 @@ elif test "${HAVE_X11}" = "yes" && test "${with_gif}" != "no" \
 fi
 AC_SUBST(LIBGIF)
 
-dnl Check for required libraries.
+dnl If using X11, warn if image libraries are missing.
+dnl It's not fatal if they're absent, though the UI may suffer.
 if test "${HAVE_X11}" = "yes"; then
   MISSING=""
   WITH_NO=""
@@ -3122,12 +3123,12 @@ if test "${HAVE_X11}" = "yes"; then
     MISSING="$MISSING libtiff" && WITH_NO="$WITH_NO --with-tiff=no"
 
   if test "X${MISSING}" != X; then
-    AC_MSG_ERROR([The following required libraries were not found:
+    AC_MSG_WARN([X11 used, but the following libraries were not found:
     $MISSING
 Maybe some development libraries/packages are missing?
-If you don't want to link with them give
+Emacs will be built without them.  To silence this warning, give
     $WITH_NO
-as options to configure])
+as options to 'configure'.])
   fi
 fi