Add --enable-sync-input, default yes.

ChangeLog

+2008-03-11  Jan Dj$(Q)Z(Brv  <jan.h.d@swipnet.se>
+
+	* configure.in: Add --enable-sync-input, default yes.
+
 2008-03-11  Glenn Morris  <rgm@gnu.org>
 
 	* Makefile.in (install-etc, mkdir): Handle directory

configure

@@ -1333,6 +1333,7 @@ Optional Features:
                           specify install directory for Emacs.app on Mac OS X
                           [DIR=/Application]
   --disable-font-backend  don't compile font-backend support
+  --enable-sync-input     compile code with sync-input
   --enable-asserts        compile code with asserts enabled
   --enable-maintainer-mode
                           enable make rules and dependencies not useful (and
@@ -2136,6 +2137,14 @@ else
 fi
 
 
+# Check whether --enable-sync-input was given.
+if test "${enable_sync_input+set}" = set; then
+  enableval=$enable_sync_input; USE_SYNC_INPUT=$enableval
+else
+  USE_SYNC_INPUT=yes
+fi
+
+
 # Check whether --enable-asserts was given.
 if test "${enable_asserts+set}" = set; then
   enableval=$enable_asserts; USE_XASSERTS=$enableval
@@ -23900,9 +23909,15 @@ echo
 if test $USE_XASSERTS = yes; then
    echo "  Compiling with asserts turned on."
    CPPFLAGS="$CPPFLAGS -DXASSERTS=1"
-   echo
 fi
 
+if test $USE_SYNC_INPUT = yes; then
+   echo "  Compiling with sync input."
+   CPPFLAGS="$CPPFLAGS -DSYNC_INPUT=1"
+fi
+
+echo
+
 if test "$USE_X_TOOLKIT" = GTK; then
   case "$canonical" in
   *cygwin*)

configure.in

@@ -173,6 +173,11 @@ AC_ARG_ENABLE(font-backend,
       USE_FONT_BACKEND=$enableval,
       USE_FONT_BACKEND=yes)
 
+AC_ARG_ENABLE(sync-input,
+[AS_HELP_STRING([--enable-sync-input], [compile code with sync-input])],
+      USE_SYNC_INPUT=$enableval,
+      USE_SYNC_INPUT=yes)
+
 AC_ARG_ENABLE(asserts,
 [AS_HELP_STRING([--enable-asserts], [compile code with asserts enabled])],
       USE_XASSERTS=$enableval,
@@ -3001,9 +3006,15 @@ echo
 if test $USE_XASSERTS = yes; then
    echo "  Compiling with asserts turned on."
    CPPFLAGS="$CPPFLAGS -DXASSERTS=1"
-   echo
 fi
 
+if test $USE_SYNC_INPUT = yes; then
+   echo "  Compiling with sync input."
+   CPPFLAGS="$CPPFLAGS -DSYNC_INPUT=1"
+fi
+
+echo
+
 if test "$USE_X_TOOLKIT" = GTK; then
   case "$canonical" in
   *cygwin*)