[Bug bootstrap/54732] [4.8 regression] Installation failure: libbacktrace rebuilds upon install when built with "make bootstrap-lean"

["ian at airs dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54732

Ian Lance Taylor <ian at airs dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-09-28
                 CC|                            |ian at airs dot com
     Ever Confirmed|0                           |1

--- Comment #1 from Ian Lance Taylor <ian at airs dot com> 2012-09-28 04:30:19 UTC ---
The problem seems to be the use of automake automatic dependencies in
conjunction with header files read from the previous stage in conjunction with
bootstrap-lean.  The library is compiled using "prev-gcc/xgcc -Bprev-gcc/". 
That causes gcc to search prev-gcc/include.  Some header files are found in
that directory, notably unwind.h, stddef.h, stdarg.h, and stdint.h.  Those
dependencies are recorded in the automake dependency file.

So far, so good.  Unfortunately bootstrap-lean removes prev-gcc when the new
stage is built.  Then when you run "make install", the libbacktrace Makefile
sees that it depends on files in prev-gcc/include.  Those files do not exist,
so the targets are automatically rebuilt.  In your case they are being rebuilt
with an older compiler, which fails.