--- a/gnatcoll.gpr	2018-06-12 21:37:42.664733336 +0200
+++ b/gnatcoll.gpr	2018-06-12 21:38:07.965360000 +0200
@@ -115,6 +115,7 @@
 
       for Switches ("gnatcoll_support.c") use
          Compiler'Switches ("C") & Extra_Switches;
+      for Driver ("C") use External ("GCC", "gcc");
 
    end Compiler;
 
--- a/src/gnatcoll-projects.ads.old	2017-11-25 14:50:06.919939453 +0100
+++ b/src/gnatcoll-projects.ads	2017-11-25 14:50:38.932387204 +0100
@@ -1917,7 +1917,8 @@
       Predefined_Source_Files : GNATCOLL.VFS.File_Array_Access;
       --  The list of source files in Predefined_Source_Path
 
-      Default_Gnatls : GNAT.Strings.String_Access := new String'("gnatls");
+      Default_Gnatls : GNAT.Strings.String_Access :=
+         new String'("@GNATLS@");
       --  The default gnatls command to run.
 
       Xrefs_Subdir : GNAT.Strings.String_Access;