The code in trap.S is to support the old APCS chunked stack variant,
which dates back to the Acorn days, so put it under #ifndef
__ARM_EABI__.
* libgloss/arm/trap.S: Use __ARM_EABI rather than PREFER_THUMB.
* newlib/libc/sys/arm/trap.S: Use __ARM_EABI rather than
__thumb2__.