rtems-bsp: Install 3rd party packages under a BSP.

Provide the paths so a package built for RTEMS can be installed
under the BSP.

Update NTP to install under the BSP.

source-builder/config/ntp-4-1.cfg

@@ -45,6 +45,14 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
   ../${source_dir_ntp}/configure \
     --host=%{_host} \
     --prefix=%{_prefix} \
+    --bindir=%{_bindir} \
+    --exec_prefix=%{_exec_prefix} \
+    --includedir=%{_includedir} \
+    --libdir=%{_libdir} \
+    --libexecdir=%{_libexecdir} \
+    --mandir=%{_mandir} \
+    --infodir=%{_infodir} \
+    --datadir=%{_datadir} \
     --disable-ipv6 \
     --disable-HOPFPCI