diff -r 5a59e4c03957 -r 4854ced3e9d7 lib/Tools/build
--- a/lib/Tools/build	Thu Jul 26 11:52:08 2012 +0200
+++ b/lib/Tools/build	Thu Jul 26 12:27:47 2012 +0200
@@ -28,7 +28,8 @@
   echo "  Options are:"
   echo "    -a           all sessions"
   echo "    -b           build target images"
-  echo "    -d DIR       additional session directory with ROOT file"
+  echo "    -d DIR       include session directory with ROOT file"
+  echo "    -g NAME      include session group NAME"
   echo "    -j INT       maximum number of jobs (default 1)"
   echo "    -n           no build -- test dependencies only"
   echo "    -o OPTION    override session configuration OPTION (via NAME=VAL or NAME)"
@@ -58,16 +59,16 @@
 
 ALL_SESSIONS=false
 BUILD_IMAGES=false
+declare -a MORE_DIRS=()
+declare -a SESSION_GROUPS=()
 MAX_JOBS=1
 NO_BUILD=false
+eval "declare -a BUILD_OPTIONS=($ISABELLE_BUILD_OPTIONS)"
 SYSTEM_MODE=false
 TIMING=false
 VERBOSE=false
 
-declare -a MORE_DIRS=()
-eval "declare -a BUILD_OPTIONS=($ISABELLE_BUILD_OPTIONS)"
-
-while getopts "abd:j:no:stv" OPT
+while getopts "abd:g:j:no:stv" OPT
 do
   case "$OPT" in
     a)
@@ -79,6 +80,9 @@
     d)
       MORE_DIRS["${#MORE_DIRS[@]}"]="$OPTARG"
       ;;
+    g)
+      SESSION_GROUPS["${#SESSION_GROUPS[@]}"]="$OPTARG"
+      ;;
     j)
       check_number "$OPTARG"
       MAX_JOBS="$OPTARG"
@@ -122,8 +126,8 @@
 fi
 
 "$ISABELLE_TOOL" java isabelle.Build \
-  "$ALL_SESSIONS" "$BUILD_IMAGES" "$MAX_JOBS" "$NO_BUILD" "$SYSTEM_MODE" "$TIMING" \
-  "$VERBOSE" "${MORE_DIRS[@]}" $'\n' "${BUILD_OPTIONS[@]}" $'\n' "$@"
+  "$ALL_SESSIONS" "$BUILD_IMAGES" "$MAX_JOBS" "$NO_BUILD" "$SYSTEM_MODE" "$TIMING" "$VERBOSE" \
+  "${MORE_DIRS[@]}" $'\n' "${SESSION_GROUPS[@]}" $'\n' "${BUILD_OPTIONS[@]}" $'\n' "$@"
 RC="$?"
 
 if [ "$NO_BUILD" = false ]; then