avr-libc: add support for avr-libc C library

This commit adds support for the avr-libc C library.
According to the project page at http://www.nongnu.org/avr-libc , the
avr-libc package provides a subset of the standard C library for Atmel
AVR 8-bit RISC microcontrollers. In addition, the library provides the
basic startup code needed by most applications.

Support for this library in crosstool-ng is only enabled for the AVR
8-bit target.

The avr-libc manual and most distributions build the AVR 8-bit gcc
toolchain with the "avr" (non-canonical) target.
Some experimentation also led to the conclusion that other (canonical)
targets are not very well supported, so we force the "avr" target for
crosstool-ng as well.

The manual also recommends building avr-libc after the final gcc build.
To accomplish this with crosstool-ng, a new do_libc_post_cc step is
added, in which currently only avr-libc performs its build, and is a
no-op for the other libc options.

Signed-off-by: Erico Nunes <nunes.erico@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/steps.mk b/steps.mk
index 1323379e..6a6e07ed 100644
--- a/steps.mk
+++ b/steps.mk
@@ -30,6 +30,7 @@ CT_STEPS := libc_check_config        \
             libc                     \
             cc_for_build             \
             cc_for_host              \
+            libc_post_cc             \
             libelf_for_target        \
             binutils_for_target      \
             debug                    \