Xtensa improvements:

- fix endianness support, allowing building uClibc linux toolchain for
  little-endian xtensa cores;
- add -mlongcalls -mtext-section-literals to xtensa-unknown-linux-uclibc
  CFLAGS.

crosstool-NG 1.20.0

1.19: create maintenance branch, update version to 1.19.0

Signed-off-by: "Yann E. MORIN" <[email protected]>

1.18: create maintenance branch, update version to 1.18.0

Signed-off-by: "Yann E. MORIN" <[email protected]>

1.17: create maintenance branch, update version to 1.17.0

Signed-off-by: "Yann E. MORIN" <[email protected]>

1.16: create maintenance branch, update version to 1.16.0

Signed-off-by: "Yann E. MORIN" <[email protected]>

1.15: update version to 1.15.3

Signed-off-by: "Yann E. MORIN" <[email protected]>

1.15: update version to 1.15.2

Signed-off-by: "Yann E. MORIN" <[email protected]>

1.15: update version to 1.15.1

Signed-off-by: "Yann E. MORIN" <[email protected]>