print alternatives config

Author: Bill-hbrhbr

tools/scripts/lib_install/linux/ubuntu-focal/install-prebuilt-packages.sh

@@ -29,3 +29,5 @@ ${privileged_command_prefix} update-alternatives --install /usr/bin/cc cc /usr/b
 ${privileged_command_prefix} update-alternatives --install /usr/bin/c++ c++ /usr/bin/g++-10 0 \
   --slave /usr/share/man/man1/c++.1.gz c++.1.gz /usr/share/man/man1/g++.1.gz
 ${privileged_command_prefix} update-alternatives --install /lib/cpp cpp /usr/bin/cpp-10 0
+
+${privileged_command_prefix} update-alternatives --config gcc