Sorry, but I cannot tell you where this ‘rm’ command can be found, because I do not have any setup for Android.
You can try to find it by yourself using the grep command, for instance.
Try something like:
grep -ir ‘rm -rf (TARGET_OBJS)’ *
…in one of the following directories:
…or maybe its already here:
…or some other script is calling ‘build-binary.mk’ with ‘(TARGET_OBJS)’, instead of ‘$(TARGET_OBJS)’.