toolchain-external: adjust logic to support Linaro 2012.05

toolchain-external: adjust logic to support Linaro 2012.05

The check_glibc function verifies that the C library of the external
toolchain is glibc. To do so, it verified that a file matching
ld-linux*.so.* or ld.so.* was found in the lib/ directory of the
toolchain's sysroot. However, with the Linaro 2012.05 toolchain, the
lib/ directory contains two links named ld-linux-armhf.so.3 and
ld-linux.so.3, which means that the first ld-linux*.so.* wildcard
expression expands to two files, which generates a syntax error for
the "test" program. We replace that with a more elaborate find+wc
combination to determine whether at least one matching file is
present.

The check_arm_abi function verifies the ABI of an ARM toolchain. For
EABI, it tested that the target name ends with eabi. However, with
Linaro 2012.05, the tuple is now arm-linux-gnueabihf (for hard float),
so we have to adjust the logic to accept this additional "hf"
specification in the tuple.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>