Error building libgcc: missing setting for CPP

[Paul Smith]

Hi all.  So, I'm trying to build a cross-compiler (on GNU/Linux) suite
from GCC 4.6.2, which includes a number of build utilities including GCC
and its libraries, binutils of course, make, gdb, fakeroot, bison, flex.

I have a makefile that did this for me and I was able to get it to work,
a year or two ago, with GCC 4.2.4, although I had to whack a few things.

Now I'm trying to update the environment with all the latest stuff,
removing the hacks as hopefully I won't need them.  I've gotten things
moving but I'm seeing two persistent problems.  The one I want to
discuss here is:

During the compilation of GCC 4.6.2, when it gets to build libgcc, the
configure is bailing on me:

checking whether ln -s works... yes
checking for x86_64-generic-linux-gnu-gcc... /usr/src/gcc/obj-base/gcc/./gcc/xgcc \
    -B/usr/src/gcc/obj-base/gcc/./gcc/ -B/tmp/invalid/generic/x86_64-generic-linux-gnu/bin/ \
    -B/tmp/invalid/generic/x86_64-generic-linux-gnu/lib/ \
    -isystem /tmp/invalid/generic/x86_64-generic-linux-gnu/include \
    -isystem /tmp/invalid/generic/x86_64-generic-linux-gnu/sys-include \
    --sysroot=/tmp/invalid/rhel5/sysroot  
checking for suffix of object files... configure: error: in `/usr/src/gcc/obj-base/gcc/x86_64-generic-linux-gnu/libgcc':
configure: error: cannot compute suffix of object files: cannot compile
See `config.log' for more details.
make[3]: *** [configure-target-libgcc] Error 1
make[3]: Leaving directory `/usr/src/gcc/obj-base/gcc'

Looking
at /usr/src/gcc/obj-base/gcc/x86_64-generic-linux-gnu/libgcc/config.log,
I get this error:

configure:3246: checking for suffix of object files
configure:3268: /usr/src/gcc/obj-base/gcc/./gcc/xgcc -B/usr/src/gcc/obj-base/gcc/./gcc/ \
    -B/tmp/invalid/generic/x86_64-generic-linux-gnu/bin/ \
    -B/tmp/invalid/generic/x86_64-generic-linux-gnu/lib/ \
    -isystem /tmp/invalid/generic/x86_64-generic-linux-gnu/include \
    -isystem /tmp/invalid/generic/x86_64-generic-linux-gnu/sys-include \
    --sysroot=/tmp/invalid/rhel5/sysroot   -c -g -O2  conftest.c >&5
/usr/src/gcc/obj-base/gcc/./gcc/as: line 87: exec: --: invalid option
exec: usage: exec [-cl] [-a name] file [redirection ...]
configure:3272: $? = 1

If I check the "as" shell script, I can see that the "ORIGINAL_*" values
are all empty:

ORIGINAL_AS_FOR_TARGET=""
ORIGINAL_LD_FOR_TARGET=""
ORIGINAL_PLUGIN_LD_FOR_TARGET=""
ORIGINAL_NM_FOR_TARGET=""

and so when we get to:

case "$invoked" in
  as)
    original=$ORIGINAL_AS_FOR_TARGET
    prog=as-new$exeext
    dir=gas
    ;;

$original is empty, and then later:

    exec $original ${1+"$@"}

we exec just the arguments, causing this problem.

I can't figure out where this is going wrong.  Can someone point me to
where these values (ORIGINAL_AS_FOR_TARGET etc.) are supposed to be set?

-- 
-------------------------------------------------------------------------------
 Paul D. Smith <psmith@gnu.org>          Find some GNU make tips at:
 http://www.gnu.org                      http://make.mad-scientist.net
 "Please remain calm...I may be mad, but I am a professional." --Mad Scientist