omni: extract_utils: export SIGSCAN

For use in device scripts

Change-Id: I7a8c9abd0b585a67963e65d5ad042da79d4d3c77
diff --git a/build/tools/extract_utils.sh b/build/tools/extract_utils.sh
index f0e8717..7c98b62 100755
--- a/build/tools/extract_utils.sh
+++ b/build/tools/extract_utils.sh
@@ -106,6 +106,10 @@
     if [ -z "$PATCHELF" ]; then
         export PATCHELF="$OMNI_ROOT"/vendor/omni/build/tools/${HOST}/bin/patchelf
     fi
+
+    if [ -z "$SIGSCAN" ]; then
+        export SIGSCAN="$OMNI_ROOT"/vendor/omni/build/tools/${HOST}/bin/SigScan
+    fi
 }
 
 # Helper functions for parsing a spec.