squid: fix old distro gcc build failure

Squid 3.5.x deprecated the use of HOSTCXX & friends in favour of
BUILDCXX and BUILDCXXFLAGS.
When they are not specified BUILDCXXFLAGS takes flags from target
CXXFLAGS which specifies C11 standard and which older vesions of gcc
don't understand, thus causing breakage.
cf_gen hasn't got any C11 features so it's not required. Fixes:
http://autobuild.buildroot.net/results/816/8162e4ec941e7642248373be47cca99113a648e8/



Also drop ACLOCAL and AUTOMAKE trickery from e27ccbab since it's no
longer required.

And fix a typo in the hash file pointing to an improper hash file
upstream.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>