Search existing value of XEN_HEADERS for Xen headers

This allows a caller to specify a specific location for the Xen
headers.  For example, from a version of Xen just built in a
neighbouring directory.

(Without this it is not possible to build against a specific Xen
without being able to overwrite system header areas.)

If XEN_HEADERS is unset, or not suitable, use the existing search
strategy.

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

diff --git a/build-rr.sh b/build-rr.sh
index 30054ca3bf93f2b89547283b812d6f312eef40f6..2bb318b77125a910af578e0a5e2631c5581859f4 100755 (executable)
--- a/build-rr.sh
+++ b/build-rr.sh
@@ -229,7 +229,7 @@ probeprereqs ()
                . "${RROBJ}/config.sh"
                # probe location of Xen headers
                found=false
-               for loc in /usr/pkg/include/xen /usr/include/xen; do
+               for loc in ${XEN_HEADERS:-} /usr/pkg/include/xen /usr/include/xen; do
                        if printf '#include <stdint.h>\n#include <xen.h>\n'\
                            | ${CC} -I${loc} -x c - -c -o /dev/null \
                            >/dev/null 2>&1 ; then