Make warning for native build

[Alexandre Oliva]

On Dec 17, 2002, DJ Delorie <dj@delorie.com> wrote:

>> Shouldn't configure comment out the configure-build-libiberty
>> related targets for native build?

> We're still pondering that issue.  Patches welcome.  Libiberty does it
> with a @foo@-style pattern prefixing the rules, which might work well
> in this case.

/me thinks BUILD_SUBDIR != TARGET_SUBDIR should always hold, so that
we use the newly build gcc to build libiberty for the target, even if
target == host == build.  An easy way to accomplish this is to prefix
BUILD_SUBDIR with build-, always or when build_alias = target_alias.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                 aoliva@{redhat.com, gcc.gnu.org}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist                Professional serial bug killer