$(XEN_ROOT) absolutification fixes for ioemu-remote (incl stubdom)

 * Move code for generating an absolute version of XEN_ROOT
   into a common make variable set in Config.mk
 * Use this common code when invoking make -C ioemu-dir clean
   from tools/, which avoids a problem where `make clean' fails
   because qemu's (ioemu-remote's) build system wants to run
   `make clean' in `tests' but XEN_ROOT is a confection involving
   ../'s.
 * Use this common code in stubdom/Makefile, instead of $(abspath...)
   as the latter is a relatively new feature in GNU make and is not
   available in all the places that we want to be able to build
   (cf c/s 17997:3f23e01d31985899dbd1660b166f229f1ee74292)

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/Config.mk b/Config.mk
index 65f2de88ec..5976c2b9a7 100644
--- a/Config.mk
+++ b/Config.mk
@@ -54,6 +54,22 @@ define cc-ver-check-closure
     endif
 endef
 
+define absolutify_xen_root
+    case "$(XEN_ROOT)" in                                          \
+    /*) XEN_ROOT=$(XEN_ROOT) ;;                                    \
+    *)  xen_root_lhs=`pwd`;                                        \
+        xen_root_rhs=$(XEN_ROOT)/;                                 \
+        while [ "x$${xen_root_rhs#../}" != "x$$xen_root_rhs" ]; do \
+            xen_root_rhs="$${xen_root_rhs#../}";                   \
+            xen_root_rhs="$${xen_root_rhs#/}";                     \
+            xen_root_rhs="$${xen_root_rhs#/}";                     \
+            xen_root_lhs="$${xen_root_lhs%/*}";                    \
+        done;                                                      \
+        XEN_ROOT="$$xen_root_lhs/$$xen_root_rhs" ;;                \
+    esac;                                                          \
+    export XEN_ROOT
+endef
+
 ifeq ($(debug),y)
 CFLAGS += -g
 endif