Use build number as context qualifier for Eclipse plugins

Change-Id: I22b5c0127c7534dadcb6f0c6f7543ba64592b420
diff --git a/eclipse/scripts/build_adt.sh b/eclipse/scripts/build_adt.sh
index d668aad..0e0f161 100755
--- a/eclipse/scripts/build_adt.sh
+++ b/eclipse/scripts/build_adt.sh
@@ -43,7 +43,7 @@
 
 # 3. Launch Tycho build
 echo Launching Tycho to build ADT plugins and bundle
-./tools/gradlew -i -b sdk/eclipse/build.gradle --no-daemon buildEclipse
+( set -x ; BUILD_NUMBER="$BNUM" ./tools/gradlew -i -b sdk/eclipse/build.gradle --no-daemon buildEclipse)
 
 echo Copying ADT plugins and bundle into destination folder
 cd "$ANDROID_SRC"