gtk: Support GTK without VTE

GTK without VTE is needed for hosts which don't support VTE (for example
all variants of MinGW), but it can also be reasonable for other hosts.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
diff --git a/configure b/configure
index aae617e..5eaa802 100755
--- a/configure
+++ b/configure
@@ -318,6 +318,7 @@
 virtio_blk_data_plane=""
 gtk=""
 gtkabi="2.0"
+vte=""
 tpm="no"
 libssh2=""
 vhdx=""
@@ -1063,6 +1064,10 @@
   ;;
   --with-gtkabi=*) gtkabi="$optarg"
   ;;
+  --disable-vte) vte="no"
+  ;;
+  --enable-vte) vte="yes"
+  ;;
   --enable-tpm) tpm="yes"
   ;;
   --disable-libssh2) libssh2="no"
@@ -1946,30 +1951,41 @@
     gtkpackage="gtk+-$gtkabi"
     if test "$gtkabi" = "3.0" ; then
       gtkversion="3.0.0"
+    else
+      gtkversion="2.18.0"
+    fi
+    if $pkg_config --exists "$gtkpackage >= $gtkversion"; then
+        gtk_cflags=`$pkg_config --cflags $gtkpackage`
+        gtk_libs=`$pkg_config --libs $gtkpackage`
+        libs_softmmu="$gtk_libs $libs_softmmu"
+        gtk="yes"
+    elif test "$gtk" = "yes"; then
+        feature_not_found "gtk" "Install gtk2 or gtk3 (requires --with-gtkabi=3.0 option to configure) devel"
+    else
+        gtk="no"
+    fi
+fi
+
+##########################################
+# VTE probe
+
+if test "$vte" != "no"; then
+    if test "$gtkabi" = "3.0"; then
       vtepackage="vte-2.90"
       vteversion="0.32.0"
     else
-      gtkversion="2.18.0"
       vtepackage="vte"
       vteversion="0.24.0"
     fi
-    if ! $pkg_config --exists "$gtkpackage >= $gtkversion"; then
-        if test "$gtk" = "yes" ; then
-            feature_not_found "gtk" "Install gtk2 or gtk3 (requires --with-gtkabi=3.0 option to configure) devel"
-        fi
-        gtk="no"
-    elif ! $pkg_config --exists "$vtepackage >= $vteversion"; then
-        if test "$gtk" = "yes" ; then
-            error_exit "libvte not found (required for gtk support)"
-        fi
-        gtk="no"
+    if $pkg_config --exists "$vtepackage >= $vteversion"; then
+        vte_cflags=`$pkg_config --cflags $vtepackage`
+        vte_libs=`$pkg_config --libs $vtepackage`
+        libs_softmmu="$vte_libs $libs_softmmu"
+        vte="yes"
+    elif test "$vte" = "yes"; then
+        feature_not_found "vte" "Install libvte or libvte-2.90 (requires --with-gtkabi=3.0 option to configure) devel"
     else
-	gtk_cflags=`$pkg_config --cflags $gtkpackage`
-	gtk_libs=`$pkg_config --libs $gtkpackage`
-	vte_cflags=`$pkg_config --cflags $vtepackage`
-	vte_libs=`$pkg_config --libs $vtepackage`
-	libs_softmmu="$gtk_libs $vte_libs $libs_softmmu"
-	gtk="yes"
+        vte="no"
     fi
 fi
 
@@ -4053,6 +4069,7 @@
 echo "pixman            $pixman"
 echo "SDL support       $sdl"
 echo "GTK support       $gtk"
+echo "VTE support       $vte"
 echo "curses support    $curses"
 echo "curl support      $curl"
 echo "mingw32 support   $mingw32"
@@ -4381,6 +4398,9 @@
 if test "$gtk" = "yes" ; then
   echo "CONFIG_GTK=y" >> $config_host_mak
   echo "GTK_CFLAGS=$gtk_cflags" >> $config_host_mak
+fi
+if test "$vte" = "yes" ; then
+  echo "CONFIG_VTE=y" >> $config_host_mak
   echo "VTE_CFLAGS=$vte_cflags" >> $config_host_mak
 fi
 if test "$xen" = "yes" ; then