--- langkit-gps-src/langkit/templates/project_file.mako.old	2017-07-11 14:19:12.841221846 +0200
+++ langkit-gps-src/langkit/templates/project_file.mako	2017-07-11 14:12:39.104981170 +0200
@@ -82,9 +82,11 @@
             for Default_Switches ("Ada") use
                Common_Ada_Cargs & ("-g", "-O0", "-gnatwe", "-gnata");
 
-            for Default_Switches ("C") use Common_C_Cargs & ("-g3", "-O0");
+            for Default_Switches ("C") use Common_C_Cargs &
+              ("-g3", "-O0", "-fPIC");
 
-            for Switches ("quex_lexer.c") use Common_C_Cargs & ("-g0", "-O0");
+            for Switches ("quex_lexer.c") use Common_C_Cargs &
+              ("-g0", "-O0", "-fPIC");
             --  This file is *huge* and the debugging information for it harms
             --  Valgrind runs. We almost never have to debug this file so
             --  this is acceptable.
@@ -111,6 +111,7 @@
                   --  ... and this prevents OOM on other platforms
             end case;
       end case;
+      for Driver ("C") use External ("GCC", "gcc");
    end Compiler;
 
    package Binder is
--- langkit-gps-src/langkit/compile_context.py.old	2017-12-13 22:12:38.689143125 +0100
+++ langkit-gps-src/langkit/compile_context.py	2017-12-13 22:13:02.446737994 +0100
@@ -1171,8 +1171,7 @@
         # the Quex specification changed from last build.
         if generate_lexer and self.cache.is_stale('quex_specification',
                                                   quex_spec):
-            quex_py_file = path.join(os.environ["QUEX_PATH"], "quex-exe.py")
-            subprocess.check_call([sys.executable, quex_py_file, "-i",
+            subprocess.check_call(["quex", "-i",
                                    quex_file,
                                    "-o", "quex_lexer",
                                    "--buffer-element-size", "4",
--- langkit-gps-src/langkit/templates/pkg_analysis_body_ada.mako.old	2017-12-26 20:47:28.461617512 +0100
+++ langkit-gps-src/langkit/templates/pkg_analysis_body_ada.mako	2017-12-26 20:47:58.912060490 +0100
@@ -2196,7 +2196,7 @@
    --  printing them.
 
    function Hash (S : Lexical_Env) return Hash_Type is
-     (Hash_Type (To_Integer (S.all'Address)));
+     (Hash_Type'Mod (To_Integer (S.all'Address)));
 
    package Address_To_Id_Maps is new Ada.Containers.Hashed_Maps
      (Lexical_Env, Integer, Hash, "=");
--- a/testsuite/testsuite_support/__init__.py.old	2018-05-02 21:40:04.977442020 +0200
+++ b/testsuite/testsuite_support/__init__.py	2018-05-02 21:40:45.422759387 +0200
@@ -68,6 +68,7 @@
         # to build it in parallel.
         if not self.global_env['options'].disable_tear_up_builds:
-            p = Run(['gprbuild', '-p', '-f', '-P',
+            p = Run(['gprbuild', '-p', '-f', '-XLIBRARY_TYPE=relocatable',
+                     '-XXMLADA_BUILD=relocatable', '-P',
                      os.path.join(self.root_dir, '..', 'langkit', 'support',
                                   'langkit_support.gpr')], output=PIPE)
             report(p, "Langkit support")
--- a/testsuite/testsuite_support/langkit_support_driver.py.old	2018-05-03 08:01:20.019944992 +0200
+++ b/testsuite/testsuite_support/langkit_support_driver.py	2018-05-03 08:02:50.146430288 +0200
@@ -36,5 +36,7 @@
             ))
 
         self.run_and_check(['gprbuild', '-p', '-P', 'p.gpr', '-gnata',
+                            '-XLIBRARY_TYPE=relocatable',
+                            '-XXMLADA_BUILD=relocatable',
                             '-cargs', '-O0', '-g'])
         self.run_and_check(['./{}'.format(source[:-4])])
+++ a/testsuite/testsuite_support/adalog_driver.py.old	2018-05-03 08:14:30.998698722 +0200
--- b/testsuite/testsuite_support/adalog_driver.py	2018-05-03 08:16:48.275417176 +0200
@@ -41,6 +41,8 @@
                 )
             ))
 
-        self.run_and_check(['gprbuild', '-p', '-P', 'p.gpr', '-cargs', '-O0',
+        self.run_and_check(['gprbuild', '-p', '-XLIBRARY_TYPE=relocatable',
+                            '-XXMLADA_BUILD=relocatable',
+                            '-P', 'p.gpr', '-cargs', '-O0',
                             '-g'])
         self.run_and_check(['./{}'.format(source[:-4])])