[Bug bootstrap/58427] New: xgcc target compilation depends on installed libgcc_s.so

["rose.garcia-eggl2fk at yopmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58427

            Bug ID: 58427
           Summary: xgcc target compilation depends on installed
                    libgcc_s.so
           Product: gcc
           Version: 4.5.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rose.garcia-eggl2fk at yopmail dot com

during target compilation (for example libssp or libstdc++) xgcc is invoked
with the usual specs:

/src/build/gcc454/gcc-4.5.4/host-x86_64-unknown-linux-gnu/gcc/xgcc
-B/src/build/gcc454/gcc-4.5.4/host-x86_64-unknown-linux-gnu/gcc/ ... conftest.c

specs:
%{static|static-libgcc:-lgcc
-lgcc_eh}%{!static:%{!static-libgcc:%{!shared-libgcc:-lgcc --as-needed -lgcc_s
--no-as-needed}%{shared-
libgcc:-lgcc_s%{!shared: -lgcc}}}}

in case binutils ld decides for some reason that libgcc_s is needed, it will
hardcode a reference to libgcc_s into DT_NEEDED.
binutils itself finds the libgcc_s.so in the -B path, and adds it, but
launching the resulting executable will fail because the *dynamic linker* has
no way of knowing that it should look for the .so in
host-x86_64-unknown-linux-gnu/gcc.

this causes the configure check for libssp and libstdc++ to fail with
"C compiler cannot create working executables".

possible solutions:
1) the spec file used by xgcc to compile target libraries should use
libgcc_eh.a instead of libgcc_s.so
2) LD_LIBRARY_PATH has to be set to host-x86_64-unknown-linux-gnu/gcc (the -B
path) so the dynamic linker can find libgcc_s.so

imo, 1) is preferable.