cc/gcc: speed up the build a little bit

Even if the current process is highly parallel, crosstool-NG spends most
of its time in single-job steps on fast machines (with a 12-CPU system,
I approximate the parallel vs. non-parallel time to be in the order os
1 to 3; that is crostool-NG spends two-thirds of its time running
non-parallel jobs).

Some steps to build gcc can be paralleled, gaining a litle bit of time
on the whole compilation.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 --- gcc-4.0.0/libstdc++-v3/include/c_std/std_cstdio.h-orig	2005-04-29 00:08:41.000000000 -0500

 +++ gcc-4.0.0/libstdc++-v3/include/c_std/std_cstdio.h	2005-04-29 00:08:45.000000000 -0500

 @@ -142,7 +142,7 @@

    using ::vsprintf;

  }

 -#if _GLIBCXX_USE_C99

 +#if _GLIBCXX_USE_C99 || defined(__UCLIBC__)

  #undef snprintf

  #undef vfscanf