Re: {host,target,build}_alias passed via environment variables

[Akim Demaille]

| Hi,
| autoconf-2.52 exhibits this arkward behavior when calling
| subdirectory configure scripts w/ cross compilation (I think this is
| closely related to the problem Andreas Schwab reported earlier.).
| 
| Given a hierachy of autoconfizcated packages:
| # find -name configure.in
| ./configure.in
| ./sub/configure.in
| ./sub/sub2/configure.in
| 
| # .configure --build=i386-xxx-linux --target=i386-yyy-linux
| ..
| configure: configuring in sub
| configure: running /bin/sh './configure'  --build=i386-xxx-linux
| --host=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux --cache-file=/dev/null --srcdir=.
| ..
| configure: configuring in sub2
| configure: running /bin/sh './configure'  --build=i386-xxx-linux
| --host=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux --cache-file=/dev/null --srcdir=.
| 
| I see two (more or less independent) severe problems:
| 
| 1. *_aliases are passed via environment variables (this is redundant
| to --[build|host|target] and _does_ desturb configure scripts which
| evaluate the arguments passed to configure (eg. in configure scripts
| which support 2- and 3-leaf Canadian crosses - Such configure
| scripts often process --[host|build|target] and actively invoke
| other configure scripts.)
| 
| 2. The *_alias'es accumulate with invocation of config.status. I.e.
| with each recursion of during initial configuration, (cf. above) and
| with each subsequent run of a directory's config.status afterwards
| (cf. below)
| 
| # ./config.status --recheck
| running /bin/sh ./configure  --build=i386-xxx-linux
| --host=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux  --no-create --no-recursion
| # ./config.status --recheck
| running /bin/sh ./configure  --build=i386-xxx-linux
| --host=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux  --no-create --no-recursion
| # ./config.status --recheck
| running /bin/sh ./configure  --build=i386-xxx-linux
| --host=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux build_alias=i386-xxx-linux
| host_alias=i386-yyy-linux  --no-create --no-recursion
| 
| Ralf
| 
| PS. Example to reproduce this behavior enclosed in the attachment
| below.

I don't know why these variables are exported :(  I'm fine with
removing them.