Enable -safe-string everywhere

Useful for testing on OCaml < 4.06.0

examples/custom-utop/jbuild

@@ -2,5 +2,6 @@
 
 (executable
  ((name myutop)
+  (flags (:standard -safe-string))
   (link_flags (-linkall))
   (libraries (utop))))

examples/interact/jbuild

@@ -2,5 +2,6 @@
 
 (executable
  ((name test_program)
+  (flags (:standard -safe-string))
   (link_flags (-linkall))
   (libraries (utop))))

src/lib/jbuild

@@ -4,6 +4,7 @@
  ((name uTop)
   (public_name utop)
   (wrapped false)
+  (flags (:standard -safe-string))
   (modes (byte))
   (libraries (compiler-libs.toplevel findlib.top lambda-term threads))
   (preprocess (action (run ${bin:cppo} -V OCAML:${ocaml_version} ${<})))))

src/top/expunge/jbuild

@@ -2,4 +2,5 @@
 
 (executable
  ((name expunge)
+  (flags (:standard -safe-string))
   (libraries (unix))))

src/top/jbuild

@@ -3,6 +3,7 @@
 (executables
  ((names (utop))
   (libraries (utop))
+  (flags (:standard -safe-string))
   (link_flags (-linkall))))
 
 (rule