Make branding bulk-configurable.

configure.in

@@ -1591,6 +1591,16 @@ dnl ===================================================================
 dnl Branding
 dnl ===================================================================
 
+AC_ARG_WITH(branding,
+[  --with-branding        Use given path to retrieve all branding images.
+                          Expects /path/intro.png ...
+                          /path/backing_rtl_right.png to be there. Individual
+                          images can be overridden via --with-intro-bitmap ...
+                          --with-startcenter-rtl-left-bitmap switches.
+
+                          Usage:     --with-branding=/path/to/images
+],,)
+
 AC_ARG_WITH(intro-bitmap,
 [  --with-intro-bitmap    Prefer the specified intro bitmap over the
                           the default one.
@@ -9224,20 +9234,6 @@ if test -n "${GIT_LINK_SRC}"; then
 fi
 AC_SUBST(GIT_LINK_SRC)
 
-AC_MSG_CHECKING([for another 'intro' bitmap])
-INTRO_BITMAP=
-if test -z "$with_intro_bitmap" -o "$with_intro_bitmap" = "no" ; then
-    INTRO_BITMAP=
-    AC_MSG_RESULT([none])
-else
-    case "$with_intro_bitmap" in
-    *.png) INTRO_BITMAP="$with_intro_bitmap" ;;
-    *)     AC_MSG_WARN([Intro bitmap should be a .png file!]) ;;
-    esac
-    AC_MSG_RESULT([$INTRO_BITMAP])
-fi
-AC_SUBST(INTRO_BITMAP)
-
 AC_MSG_CHECKING([for custom 'intro' progress bar color])
 PROGRESSBARCOLOR=
 if test -z "$with_intro_progressbar_color" ; then
@@ -9282,10 +9278,58 @@ else
 fi
 AC_SUBST(PROGRESSFRAMECOLOR)
 
-AC_MSG_CHECKING([for another 'about' bitmap])
+AC_MSG_CHECKING([for alternative branding images directory])
+INTRO_BITMAP=
 ABOUT_BITMAP=
+STARTCENTER_LEFT_BITMAP=
+STARTCENTER_RIGHT_BITMAP=
+STARTCENTER_RTL_LEFT_BITMAP=
+STARTCENTER_RTL_RIGHT_BITMAP=
+STARTCENTER_SPACE_BITMAP=
+if test -z "$with_branding" -o "$with_branding" = "no" ; then
+    AC_MSG_RESULT([none])
+else
+    INTRO_BITMAP="$with_branding/intro.png"
+    ABOUT_BITMAP="$with_branding/about.png"
+    STARTCENTER_LEFT_BITMAP="$with_branding/backing_left.png"
+    STARTCENTER_RIGHT_BITMAP="$with_branding/backing_right.png"
+    STARTCENTER_RTL_LEFT_BITMAP="$with_branding/backing_rtl_left.png"
+    STARTCENTER_RTL_RIGHT_BITMAP="$with_branding/backing_rtl_right.png"
+    STARTCENTER_SPACE_BITMAP="$with_branding/backing_space.png"
+    for i in $INTRO_BITMAP \
+             $ABOUT_BITMAP \
+             $STARTCENTER_LEFT_BITMAP \
+             $STARTCENTER_RIGHT_BITMAP \
+             $STARTCENTER_RTL_LEFT_BITMAP \
+             $STARTCENTER_RTL_RIGHT_BITMAP \
+             $STARTCENTER_SPACE_BITMAP; do
+        if test ! -f $i; then
+            AC_MSG_WARN([Required file $i does not exist!])
+        fi
+    done
+    AC_MSG_RESULT([$with_branding])
+fi
+
+AC_MSG_CHECKING([for yet another 'intro' bitmap])
+if test -z "$with_intro_bitmap" -o "$with_intro_bitmap" = "no" ; then
+    if test "$with_intro_bitmap" = "no" ; then
+        INTRO_BITMAP=
+    fi
+    AC_MSG_RESULT([none])
+else
+    case "$with_intro_bitmap" in
+    *.png) INTRO_BITMAP="$with_intro_bitmap" ;;
+    *)     AC_MSG_WARN([Intro bitmap should be a .png file!]) ;;
+    esac
+    AC_MSG_RESULT([$INTRO_BITMAP])
+fi
+AC_SUBST(INTRO_BITMAP)
+
+AC_MSG_CHECKING([for yet another 'about' bitmap])
 if test -z "$with_about_bitmap" -o "$with_about_bitmap" = "no" ; then
-    ABOUT_BITMAP=
+    if test "$with_about_bitmap" = "no" ; then
+        ABOUT_BITMAP=
+    fi
     AC_MSG_RESULT([none])
 else
    case "$with_about_bitmap" in
@@ -9296,10 +9340,11 @@ else
 fi
 AC_SUBST(ABOUT_BITMAP)
 
-AC_MSG_CHECKING([for another 'start center left' bitmap])
-STARTCENTER_LEFT_BITMAP=
+AC_MSG_CHECKING([for yet another 'start center left' bitmap])
 if test -z "$with_startcenter_left_bitmap" -o "$with_startcenter_left_bitmap" = "no" ; then
-   STARTCENTER_LEFT_BITMAP=
+   if test "$with_startcenter_left_bitmap" = "no" ; then
+      STARTCENTER_LEFT_BITMAP=
+   fi
    AC_MSG_RESULT([none])
 else
    case "$with_startcenter_left_bitmap" in
@@ -9310,10 +9355,11 @@ else
 fi
 AC_SUBST(STARTCENTER_LEFT_BITMAP)
 
-AC_MSG_CHECKING([for another 'start center right' bitmap])
-STARTCENTER_RIGHT_BITMAP=
+AC_MSG_CHECKING([for yet another 'start center right' bitmap])
 if test -z "$with_startcenter_right_bitmap" -o "$with_startcenter_right_bitmap" = "no" ; then
-   STARTCENTER_RIGHT_BITMAP=
+   if test "$with_startcenter_right_bitmap" = "no" ; then
+      STARTCENTER_RIGHT_BITMAP=
+   fi
    AC_MSG_RESULT([none])
 else
    case "$with_startcenter_right_bitmap" in
@@ -9324,10 +9370,11 @@ else
 fi
 AC_SUBST(STARTCENTER_RIGHT_BITMAP)
 
-AC_MSG_CHECKING([for another 'start center rtl left' bitmap])
-STARTCENTER_RTL_LEFT_BITMAP=
+AC_MSG_CHECKING([for yet another 'start center rtl left' bitmap])
 if test -z "$with_startcenter_rtl_left_bitmap" -o "$with_startcenter_rtl_left_bitmap" = "no" ; then
-   STARTCENTER_RTL_LEFT_BITMAP=
+   if test "$with_startcenter_rtl_left_bitmap" = "no" ; then
+      STARTCENTER_RTL_LEFT_BITMAP=
+   fi
    AC_MSG_RESULT([none])
 else
    case "$with_startcenter_rtl_left_bitmap" in
@@ -9338,10 +9385,11 @@ else
 fi
 AC_SUBST(STARTCENTER_RTL_LEFT_BITMAP)
 
-AC_MSG_CHECKING([for another 'start center rtl right' bitmap])
-STARTCENTER_RTL_RIGHT_BITMAP=
+AC_MSG_CHECKING([for yet another 'start center rtl right' bitmap])
 if test -z "$with_startcenter_rtl_right_bitmap" -o "$with_startcenter_rtl_right_bitmap" = "no" ; then
-   STARTCENTER_RTL_RIGHT_BITMAP=
+   if test "$with_startcenter_rtl_right_bitmap" = "no" ; then
+      STARTCENTER_RTL_RIGHT_BITMAP=
+   fi
    AC_MSG_RESULT([none])
 else
    case "$with_startcenter_rtl_right_bitmap" in
@@ -9352,10 +9400,11 @@ else
 fi
 AC_SUBST(STARTCENTER_RTL_RIGHT_BITMAP)
 
-AC_MSG_CHECKING([for another 'start center space' bitmap])
-STARTCENTER_SPACE_BITMAP=
+AC_MSG_CHECKING([for yet another 'start center space' bitmap])
 if test -z "$with_startcenter_space_bitmap" -o "$with_startcenter_space_bitmap" = "no" ; then
-   STARTCENTER_SPACE_BITMAP=
+   if test "$with_startcenter_space_bitmap" = "no" ; then
+      STARTCENTER_SPACE_BITMAP=
+   fi
    AC_MSG_RESULT([none])
 else
    case "$with_startcenter_space_bitmap" in