component/gcc: use SlapOS binutils when building gcc.

also drop non-existing '--with-nm' option.

component/gcc/buildout.cfg

@@ -29,11 +29,10 @@ configure-options =
   --enable-languages="c,c++,fortran"
   --with-isl=${isl:location}
   --with-ld=${binutils:location}/bin/ld
-  --with-nm=${binutils:location}/bin/nm
   --with-as=${binutils:location}/bin/as
 environment =
   LDFLAGS=-Wl,-rpath=${gmp:location}/lib -Wl,-rpath=${isl:location}/lib -Wl,-rpath=${mpc:location}/lib -Wl,-rpath=${mpfr:location}/lib
-  PATH=${perl:location}/bin:${tar:location}/bin:%(PATH)s
+  PATH=${binutils:location}/bin:${perl:location}/bin:${tar:location}/bin:%(PATH)s
 
 [gcc-minimal]
 <= gcc-common