Increase number of threads used by build_all.sh

Change-Id: I97e1bd30fb6e237d50b72c3acd4668759a381d0a
diff --git a/sl4a/build_all.sh b/sl4a/build_all.sh
index 9cd5c1b..f5392e8 100755
--- a/sl4a/build_all.sh
+++ b/sl4a/build_all.sh
@@ -76,13 +76,13 @@
 do
   echo -e "${lb}+++++++ Building ${i} +++++++${NC}"
   cd $SL4A_ROOT/"${i}"
-  exec mm -B "building ${i}"
+  exec mm -j8 -B "building ${i}"
   echo
 done
 
 echo -e "${lb}+++++++ Building ${APP_NAME}.apk +++++++${NC}"
 cd ${SL4A_PROJ_DIR}
-exec mm -B "building ${APP_NAME}.apk"
+exec mm -j8 -B "building ${APP_NAME}.apk"
 echo
 
 }