utils.bbclass: ensure $0 is correct in wrapper scripts
Some packages (eg mesa) will invoke a tool with --version and do string matches
on the output (i.e. mesa does $LEX --version |grep "^flex "). This doesn't work
with the combination of wrapper scripts and binaries that use $0 as they output
"flex.real".
Luckily bash's exec lets you set $0. As we want to use this we can't use env,
but using export appears to work just as well.
Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
