Thanks!
The option was -v not -va, but now it displays all info.
And so, it hangs in this command:
C:\android\android-ndk-r9d\toolchains\arm-linux-androideabi-4.8\prebuilt\windows\bin\arm-linux-androideabi-as.exe -mfpu=vfpv3 -o d:\code\fpc\packages\rtl-unicode\units\arm-android\cp936.o d:\code\fpc\packages\rtl-unicode\units\arm-android\cp936.s
Now, now, copypasting this comand into the command line, it runs fine.
However, notice the following, this command is generating an .o file.
When compiling FPC with make, it does indeed also generate this file, so it seems that the next step is the culprit (which I assume it is making a ppu from the .o).