Toolchain+Ports: Use the GNU hash format by default

This hash format offers faster symbol lookup than the System V hash.

We've been using it in all our shared libraries for a long time, but did
not have it enabled by default in our toolchain, so ports couldn't make
use of it.

Toolchain/BuildIt.sh

@@ -380,6 +380,7 @@ pushd "$DIR/Build/$ARCH"
                                             --enable-lto \
                                             --enable-threads=posix \
                                             --enable-initfini-array \
+                                            --with-linker-hash-style=gnu \
                                             ${TRY_USE_LOCAL_TOOLCHAIN:+"--quiet"} || exit 1
 
         echo "XXX build gcc and libgcc"