To build uClibc correctly we need correct endianness selected in the
crosstool-NG. Xtensa cores may be little- or big-endian, but this
property is static. The toolchain knows the core endianness and doesn't
need options to select it.
Enable ARCH_SUPPORTS_BOTH_ENDIAN and select LE by default. Specify empty
CT_ARCH_ENDIAN_CFLAG so that -m{big,little}-endian don't get added to
the TARGET_CFLAGS, as it's not supported by gcc. Specify empty
CT_ARCH_ENDIAN_LDFLAG so that -EB/-EL don't get added to the
TARGET_LDFLAGS as they are ignored. Select big-endian in the example
xtensa-unknown-linux-uclibc configuration.
This fixes uClibc toolchain build for little-endian cores.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>