[dunecontrol] support out-of-tree builds

up to now you could specify a BUILDDIR variable, which implied that modules were built in
$srdir/$BUILDDIR.
Imagine you have your dune modules in $HOME/Src. When you set BUILDDIR=build.g++
your dune-common module is built in $HOME/Src/dune-common/build.g++
Now you change BUILDDIR to an absolute path, e.g. BUILDDIR=$HOME/Build.g++
With the latest change dunecontrol will now build dune-common in
$HOME/Build.g++/dune-common/

Thanks to Angar for bugging me :-)

bin/dunecontrol

@@ -132,6 +132,7 @@ build_module() {
       set -e
       cd "$path"
       export module
+	  export ABS_BUILDDIR=$(abs_builddir $module $BUILDDIR)
       eval_control $runcommand "$path/$CONTROL"
     ); then eval echo "--- Failed to build \$NAME_${module} ---"; exit 1; fi
 	trap onfailure EXIT
@@ -173,8 +174,8 @@ load_opts() {
         fi
       fi
       if test -n "$USE_CMAKE" && test -z "$CMAKE"; then
-	# We use cmake for building, but CMAKE is not yet set.
-	# Check the opts file for it
+        # We use cmake for building, but CMAKE is not yet set.
+        # Check the opts file for it
         OPTS_FILE_CMAKE="$(eval CMAKE=""; . $DUNE_OPTS_FILE; eval echo \$CMAKE)"
         if test -n "$OPTS_FILE_CMAKE"; then
           CMAKE="$OPTS_FILE_CMAKE"
@@ -198,7 +199,7 @@ load_opts() {
   elif test -n "$CMD_FLAGS"; then
     echo "----- using default flags \$${COMMAND}_FLAGS from environment -----"
   fi
-  
+
   if test "x$USE_CMAKE" = "xyes"; then
     if test -z "$BUILDDIR"; then
       echo "No build directory provided. Defaulting to the sub directory build-cmake"
@@ -207,6 +208,22 @@ load_opts() {
   fi
 }
 
+abs_builddir()
+{
+  local m=$1
+  local builddir=$2
+  local name="$(eval echo \$NAME_$m)"
+  local path="$(eval echo \$PATH_$m)"
+  case $BUILDDIR in
+	  /*)
+		  echo $builddir/$name
+		  ;;
+	  *)
+		  echo $path/$builddir
+		  ;;
+  esac
+}
+
 space=" "
 tab="	"
 BLANK="$space$tab"
@@ -334,10 +351,10 @@ done
 run_default_exec () { bash -c "eval $CMD_FLAGS"; }
 
 run_default_bexec () {
-  if test -d "$BUILDDIR"; then
-    bash -c "cd \"$BUILDDIR\" && eval $CMD_FLAGS";
+  if test -d "$ABS_BUILDDIR"; then
+    bash -c "cd \"$ABS_BUILDDIR\" && eval $CMD_FLAGS";
   else
-    eval echo "Build directory \\\"$BUILDDIR\\\" not found, skipping bexec for \$NAME_${module}"
+    eval echo "Build directory \\\"$ABS_BUILDDIR\\\" not found, skipping bexec for \$NAME_${module}"
   fi
 }
 
@@ -621,16 +638,17 @@ run_default_configure () {
             ACLOCAL_FLAGS="$ACLOCAL_FLAGS -I $dir"
         fi
       done
-      if test -d "$path/$BUILDDIR"; then
-        PARAMS="$PARAMS \"--with-$name=$path/$BUILDDIR\""
+	  local m_ABS_BUILDDIR=$(abs_builddir $m $BUILDDIR)
+      if test -d "$m_ABS_BUILDDIR"; then
+        PARAMS="$PARAMS \"--with-$name=$m_ABS_BUILDDIR\""
       else
         if test x$(eval echo \$INST_$m) != xyes; then
           PARAMS="$PARAMS \"--with-$name=$path\""
         fi
       fi
       if test "x$LOCAL_USE_CMAKE" = "xyes"; then
-          if test -d "$path/$BUILDDIR"; then
-	      CMAKE_PARAMS="$CMAKE_PARAMS \"-D""$name""_DIR=$path/$BUILDDIR\""
+          if test -d "$m_ABS_BUILDDIR"; then
+	      CMAKE_PARAMS="$CMAKE_PARAMS \"-D""$name""_DIR=$m_ABS_BUILDDIR\""
           else
 	      TMP_PARAMS="\"-D""$name""_DIR=$path\""
 	      for i in $MULTIARCH_LIBDIR lib lib64 lib32; do
@@ -664,19 +682,19 @@ run_default_configure () {
         fi
       done
       # create build directory if requested
-      test -d "$BUILDDIR" || mkdir -p "$BUILDDIR"
+      test -d "$ABS_BUILDDIR" || mkdir -p "$ABS_BUILDDIR"
       SRCDIR="$PWD"
-      cd "$BUILDDIR"
+      cd "$pwd; ABS_BUILDDIR"
       echo "$PREPARAMS $CMAKE -DCMAKE_MODULE_PATH=\"$CMAKE_MODULE_PATH\" $CMAKE_PARAMS $CMAKE_FLAGS \"$SRCDIR\""
       eval $PREPARAMS $CMAKE "-DCMAKE_MODULE_PATH=\"$CMAKE_MODULE_PATH\" $CMAKE_PARAMS $CMAKE_FLAGS \"$SRCDIR\"" || exit 1
     else
       PARAMS="$PARAMS ACLOCAL_AMFLAGS=\"$ACLOCAL_FLAGS\""
       echo ./configure "$PARAMS"
       # create build directory if requested
-      if test -n "$BUILDDIR"; then
-        test -d "$BUILDDIR" || mkdir -p "$BUILDDIR"
+      if test -n "$ABS_BUILDDIR"; then
+        test -d "$ABS_BUILDDIR" || mkdir -p "$ABS_BUILDDIR"
         SRCDIR="$PWD"
-        cd "$BUILDDIR"
+        cd "$ABS_BUILDDIR"
         eval "$SRCDIR/configure" "$PARAMS" || exit 1
       else
         eval ./configure "$PARAMS" || exit 1
@@ -696,7 +714,7 @@ run_default_configure () {
 }
 
 run_default_make () {
-  test ! -d "$BUILDDIR" || cd "$BUILDDIR"
+  test ! -d "$ABS_BUILDDIR" || cd "$ABS_BUILDDIR"
   PARAMS="$CMD_FLAGS"
   echo make "$PARAMS"
   eval $MAKE "$PARAMS"