Re: configure fails with gcc 4.6.0 LTO

[Greg Wooledge]

On Sat, Mar 19, 2011 at 09:52:05PM +0000, Zeev Tarantov wrote:
> configure:3122: checking for C compiler default output file name
> configure:3144: x86_64-pc-linux-gnu-gcc -g -O2 -flto
> -DDEFAULT_PATH_VALUE='"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"'
> -DSTANDARD_UTILS_PATH='"/bin:/usr/bin:/sbin:/usr/sbin"'
> -DSYS_BASHRC='"/etc/bash/bashrc"'
> -DSYS_BASH_LOGOUT='"/etc/bash/bash_logout"'
> -DNON_INTERACTIVE_LOGIN_SHELLS -DSSH_SOURCE_BASHRC -Wl,-flto
> conftest.c  >&5
> x86_64-pc-linux-gnu-gcc: error: \: No such file or directory
> x86_64-pc-linux-gnu-gcc: error: \: No such file or directory
> x86_64-pc-linux-gnu-gcc: error: \: No such file or directory
> x86_64-pc-linux-gnu-gcc: error: \: No such file or directory
> lto-wrapper: 
> /usr/x86_64-pc-linux-gnu/gcc-bin/4.6.0-pre9999/x86_64-pc-linux-gnu-gcc
> returned 1 exit status

I'm not sure how much of the distortion we're seeing here is being
caused by a mail user agent, versus how much is caused by the experimental
gcc he's using, etc.

My guess, without knowing anything about this version of gcc, is that
the command that ./configure is supposed to execute is really something
like:

x86_64-pc-linux-gnu-gcc -g -O2 -flto \
 
-DDEFAULT_PATH_VALUE='"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"'
 \
 -DSTANDARD_UTILS_PATH='"/bin:/usr/bin:/sbin:/usr/sbin"' \

and so on, where the backslashes are supposed to be at the ends of the
lines, to indicate continuation.  And somewhere along the way, they're
being doubled so that they're becoming literal words.

imadev:/tmp$ /net/appl/gcc-3.3/bin/gcc -g -O2 -DFOO=BAR \\ -DQWERTY=UIOP \\ 
hello.c
gcc: \: No such file or directory
gcc: \: No such file or directory

Kinda like that.

Maybe it's gcc 4.6-prewhatever that's doing it.  Maybe he's actually using
some sort of "build system wrapper" that's broken.  I don't know.  I just
recognize the symptom, not the cause.