Toolchain: Allow building shared objects

Here goes a small first step towards dynamic linking.

Toolchain/BuildIt.sh

@@ -100,6 +100,7 @@ pushd "$DIR/Build/"
  "$DIR"/Tarballs/binutils-2.33.1/configure --prefix="$PREFIX" \
  --target="$TARGET" \
  --with-sysroot="$SYSROOT" \
+ --enable-shared \
  --disable-nls || exit 1
  make -j "$MAKEJOBS" || exit 1
  make install || exit 1
@@ -111,6 +112,7 @@ pushd "$DIR/Build/"
  --with-sysroot="$SYSROOT" \
  --disable-nls \
  --with-newlib \
+ --enable-shared \
  --enable-languages=c,c++ || exit 1
 
  echo "XXX build gcc and libgcc"

Toolchain/Patches/gcc.patch

@@ -137,10 +137,10 @@ index 000000000..24b29c3da
 +#define PTRDIFF_TYPE "long int"
 diff --git a/gcc/config/serenity.h b/gcc/config/serenity.h
 new file mode 100644
-index 000000000..60ebec583
+index 000000000..925c88dd6
 --- /dev/null
 +++ b/gcc/config/serenity.h
-@@ -0,0 +1,28 @@
+@@ -0,0 +1,31 @@
 +/* Useful if you wish to make target-specific GCC changes. */
 +#undef TARGET_SERENITY
 +#define TARGET_SERENITY 1
@@ -158,6 +158,9 @@ index 000000000..60ebec583
 +/* Files that are linked after user code. */
 +#undef ENDFILE_SPEC
 +#define ENDFILE_SPEC "crtend.o%s crtn.o%s"
++
++#undef LINK_SPEC
++#define LINK_SPEC "%{shared:-shared} %{static:-static} %{!shared: %{!static: %{rdynamic:-export-dynamic}}}"
 + 
 +/* Additional predefined macros. */
 +#undef TARGET_OS_CPP_BUILTINS