ensure posix, remove bashism build..sh

build-android-app.sh

@@ -49,7 +49,7 @@ DOCKERFILEEOF
 }
 
 printf $'\033[0;33m'"$(date -Iseconds) starting build"'$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n'$'\033[0m'
-diff Dockerfile <(DockerfileContent) 2>/dev/null > /dev/null || {
+DockerfileContent | diff Dockerfile - 2>/dev/null > /dev/null || {
     test -f Dockerfile && {
         read -p 'reset/start Dockerfile[Y/n]' YES
         test "$YES" = "n" && { echo "aborting..." >&2; exit 1; }