gnu: gcc: Add a "lib" output.
* gnu/packages/gcc.scm (gcc-4.7)[configure-flags]: Add
--with-gxx-include-dir.
[outputs]: New field.
[arguments] <phases>: Adjust to use the "lib" output. Add
'substitute*' calls for "libstdc++-v3/python/Makefile.in" and
"gcc/config.in".
* gnu/packages/base.scm (gcc-boot0) <symlink-libgcc_eh>: Use the "lib"
output.
(cross-gcc-wrapper): Add 'outputs' field.
(glibc-final)[arguments]: Adjust #:allowed-references to list
'(GCC-BOOT0 "lib").
(libstdc++): Add 'outputs' field.
(gcc-final)[arguments]: Add "lib" to #:allowed-references.
* gnu/packages/make-bootstrap.scm (%gcc-static): Add 'outputs' field.