Build dynamically linked executables by default

Fixes #2184

repos/hello_tutorial/doc/hello_tutorial.txt

@@ -397,7 +397,7 @@ script, which can be executed directly from within your build directory.
 A run script for the hello client-server scenario should be placed
 at the _run/hello.run_ and look as follows:
 
-!build { core init hello }
+!build { core ld.lib.so init hello }
 !
 !create_boot_directory
 !

repos/hello_tutorial/run/hello.run

@@ -31,7 +31,7 @@ install_config {
 # Boot image
 #
 
-build_boot_image { core init hello_client hello_server }
+build_boot_image { core ld.lib.so init hello_client hello_server }
 
 append qemu_args " -nographic "