--- work/langkit-gps-src/langkit/templates/project_file.mako.old	2017-07-11 14:19:12.841221846 +0200
+++ work/langkit-gps-src/langkit/templates/project_file.mako	2017-07-11 14:12:39.104981170 +0200
@@ -82,9 +82,9 @@
             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
--- work/libadalang-gps-src/ada/testsuite/testsuite_support/capi_driver.py	2017-07-30 16:01:31.495287196 +0200
+++ work/libadalang-gps-src/ada/testsuite/testsuite_support/capi_driver.py.old	2017-07-30 16:00:08.104464440 +0200
@@ -72,6 +72,7 @@
                        --  different default standard.
 
                        "-I{support_include_dir}", "-g");
+                   for Driver ("C") use External ("GCC", "gcc");
                 end Compiler;
             end P;
             '''.format(main_source=compile_units[0],
--- work/langkit-gps-src/langkit/compile_context.py.old	2017-12-13 22:12:38.689143125 +0100
+++ work/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",