fixits: sort them before applying them

[Akim Demaille]

commit 7aa38561f71d44dac3697324dd2d19cce74f9170
Author: Akim Demaille <address@hidden>
Date:   Sat May 4 17:52:51 2019 +0200

    fixits: sort them before applying them
    
    An experimental commit introduced a fix-it hint that changes comments
    such as "/* empty */" into %empty.  But in some case, because
    diagnostics are not necessarily emitted in order, the fixits also come
    in disorder, which must never happen, as the fixes are installed in
    one pass.
    
    * src/fixits.c (fixits_register): Insert them in order.

diff --git a/src/fixits.c b/src/fixits.c
index 3a8bf481..97c50569 100644
--- a/src/fixits.c
+++ b/src/fixits.c
@@ -52,6 +52,11 @@ fixit_new (location const *loc, char const* fix)
   return res;
 }
 
+static int
+fixit_cmp (const  fixit *a, const fixit *b)
+{
+  return location_cmp (a->location, b->location);
+}
 
 static void
 fixit_free (fixit *f)
@@ -85,7 +90,7 @@ fixits_register (location const *loc, char const* fix)
                                    (gl_listelement_dispose_fn) fixit_free,
                                    true);
   fixit *f = fixit_new (loc, fix);
-  gl_list_add_last (fixits, f);
+  gl_sortedlist_add (fixits, (gl_listelement_compar_fn) fixit_cmp, f);
   if (feature_flag & feature_fixit_parsable)
     fixit_print (f, stderr);
 }