Re:binutils-2.26 configure doesn't fall back to 'ar' if it can't find 'x86_64-unknown-linux-gnu-ar'

[Alastair Hughes]

I'm currently configuring binutils with:

./configure \
        --prefix="${_toolroot}" \
        --host="${_local_triplet}" \
        --target="${_target_triplet}" \
        --with-sysroot="${_sysroot}" \
        --disable-nls --disable-multilib \
        --disable-static --disable-werror \
        --with-lib-path="${_toolroot}/lib"

which works fine for 2.25. In this case, 
_local_triplet="x86_64-unknown-linux-gnu", while 
_target_triplet="mips-linux-musl".
It's also fairly similar to how CLFS does it 
(http://clfs.org/view/CLFS-3.0.0-SYSTEMD/mips/cross-tools/binutils.html), so it 
*should* be about right?

In any case, it appears that the 2.25 configure script detected the build 
system as 'x86_64-unknown-linux-gnu', while the 2.26 configure script detects 
the build system as 'x86_64-pc-linux-gnu'. Thanks for the hint!
This was changed by upstream:
http://git.savannah.gnu.org/gitweb/?p=config.git;a=commitdiff;h=ca9bfb8cc75a2be1819d89c664a867785c96c9ba;hp=1c8b09aec7b36055f10c59c587a13a9828091492
and then merged:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=5960642af99c6dc84b28e1bc69a617099b9dee97
Relevant mailing list thread:
http://lists.gnu.org/archive/html/config-patches/2015-06/msg00013.html

So it appears that I either need to add --build, or I need to change the host 
triplet to x86_64-pc-linux-gnu? Which would be better?
I assume that this not a bug (just a configuration issue on my part).

Alastair Hughes