the wildcard rule should work, but keep in mind two things:
- first, the build scripts are all run from the top-level NDK directory
- the content of LOCAL_SRC_FILES on the other hand must be relative to LOCAL_PATH
so you will end up with something like this:
MY_PREFIX := $(LOCAL_PATH)/subdir/
MY_SOURCES := $(wildcard $(MY_PREFIX)/*.c)
LOCAL_SRC_FILES += $(MY_SOURCES:$(MY_PREFIX)%=%)