diff --git a/bindings/python/wscript b/bindings/python/wscript
index 6732b4e5d..7f6d707c4 100644
--- a/bindings/python/wscript
+++ b/bindings/python/wscript
@@ -354,8 +354,8 @@ def get_module_path(bld, module):
 class apiscan_task(Task.Task):
     """Uses castxml to scan the file 'everything.h' and extract API definitions.
     """
-    after = 'gen_ns3_module_header ns3header'
-    before = 'cxx command'
+    before = ['cxxprogram', 'cxxshlib', 'cxxstlib', 'command']
+    after = ['gen_ns3_module_header', 'ns3header']
     color = "BLUE"
     def __init__(self, curdirnode, env, bld, target, cflags, module):
         self.bld = bld
@@ -460,7 +460,7 @@ def get_modules_and_headers(bld):
 
 class gen_ns3_compat_pymod_task(Task.Task):
     """Generates a 'ns3.py' compatibility module."""
-    before = 'cxx'
+    before = ['cxxprogram', 'cxxshlib', 'cxxstlib']
     color = 'BLUE'
 
     def run(self):
diff --git a/contrib/wscript b/contrib/wscript
index 60131b341..8b8294f72 100644
--- a/contrib/wscript
+++ b/contrib/wscript
@@ -212,7 +212,7 @@ def ns3_python_bindings(bld):
     bindgen = bld(features='command', source=source, target=target, command=argv)
     bindgen.env['FEATURES'] = ','.join(features)
     bindgen.dep_vars = ['FEATURES', "GCC_RTTI_ABI_COMPLETE"]
-    bindgen.before = 'cxx'
+    bindgen.before = ['cxxprogram', 'cxxshlib', 'cxxstlib']
     bindgen.after = 'gen_ns3_module_header'
     bindgen.name = "pybindgen(ns3 module %s)" % module
     bindgen.install_path = None
diff --git a/src/wscript b/src/wscript
index c6d7bf289..9a02b3e5e 100644
--- a/src/wscript
+++ b/src/wscript
@@ -252,8 +252,6 @@ def ns3_python_bindings(bld):
     bindgen = bld(features='command', source=source, target=target, command=argv)
     bindgen.env['FEATURES'] = ','.join(features)
     bindgen.dep_vars = ['FEATURES', "GCC_RTTI_ABI_COMPLETE"]
-    bindgen.before = 'cxx'
-    bindgen.after = 'gen_ns3_module_header'
     bindgen.name = "pybindgen(ns3 module %s)" % module
     bindgen.install_path = None
 
@@ -321,7 +319,7 @@ def build(bld):
         modheader.module = module.split('/')[-1]
 
 class ns3pcfile(Task.Task):
-    after = 'cxx'
+    after = ['cxxprogram', 'cxxshlib', 'cxxstlib']
 
     def __str__(self):
         "string to display to the user"
@@ -461,7 +459,7 @@ def apply_ns3header(self):
 
 
 class ns3header(Task.Task):
-    before = 'cxx gen_ns3_module_header'
+    before = ['cxxprogram', 'cxxshlib', 'cxxstlib', 'gen_ns3_module_header']
     color = 'BLUE'
 
     def __str__(self):
@@ -552,7 +550,7 @@ def apply_ns3privateheader(self):
     self.source = '' # tell WAF not to process these files further
 
 class ns3privateheader(Task.Task):
-    before = 'cxx gen_ns3_module_header'
+    before = ['cxxprogram', 'cxxshlib', 'cxxstlib', 'gen_ns3_module_header']
     after = 'ns3header'
     color = 'BLUE'
 
@@ -622,7 +620,7 @@ class ns3privateheader(Task.Task):
 
 
 class gen_ns3_module_header(Task.Task):
-    before = 'cxx'
+    before = ['cxxprogram', 'cxxshlib', 'cxxstlib']
     after = 'ns3header'
     color = 'BLUE'
 
diff --git a/wscript b/wscript
index 036eec044..a95cca0b0 100644
--- a/wscript
+++ b/wscript
@@ -689,7 +689,7 @@ def configure(conf):
 class SuidBuild_task(Task.Task):
     """task that makes a binary Suid
     """
-    after = 'link'
+    after = ['cxxprogram', 'cxxshlib', 'cxxstlib']
     def __init__(self, *args, **kwargs):
         super(SuidBuild_task, self).__init__(*args, **kwargs)
         self.m_display = 'build-suid'
@@ -1174,65 +1174,6 @@ class CheckContext(Context.Context):
         wutils.bld = bld
         wutils.run_python_program("test.py -n -c core", bld.env)
 
-
-class print_introspected_doxygen_task(Task.TaskBase):
-    after = 'cxx link'
-    color = 'BLUE'
-
-    def __init__(self, bld):
-        self.bld = bld
-        super(print_introspected_doxygen_task, self).__init__(generator=self)
-        
-    def __str__(self):
-        return 'print-introspected-doxygen\n'
-
-    def runnable_status(self):
-        return Task.RUN_ME
-
-    def run(self):
-        ## generate the trace sources list docs
-        env = wutils.bld.env
-        proc_env = wutils.get_proc_env()
-        try:
-            program_obj = wutils.find_program('print-introspected-doxygen', env)
-        except ValueError: # could happen if print-introspected-doxygen is
-                           # not built because of waf configure
-                           # --enable-modules=xxx
-            pass
-        else:
-            prog = program_obj.path.find_or_declare(ccroot.get_target_name(program_obj)).get_bld().abspath(env)
-
-            # Create a header file with the introspected information.
-            doxygen_out = open(os.path.join('doc', 'introspected-doxygen.h'), 'w')
-            if subprocess.Popen([prog], stdout=doxygen_out, env=proc_env).wait():
-                raise SystemExit(1)
-            doxygen_out.close()
-        
-            # Create a text file with the introspected information.
-            text_out = open(os.path.join('doc', 'ns3-object.txt'), 'w')
-            if subprocess.Popen([prog, '--output-text'], stdout=text_out, env=proc_env).wait():
-                raise SystemExit(1)
-            text_out.close()
-
-class run_python_unit_tests_task(Task.TaskBase):
-    after = 'cxx link'
-    color = 'BLUE'
-
-    def __init__(self, bld):
-        self.bld = bld
-        super(run_python_unit_tests_task, self).__init__(generator=self)
-        
-    def __str__(self):
-        return 'run-python-unit-tests\n'
-
-    def runnable_status(self):
-        return Task.RUN_ME
-
-    def run(self):
-        proc_env = wutils.get_proc_env()
-        wutils.run_argv([self.bld.env['PYTHON'], os.path.join("..", "utils", "python-unit-tests.py")],
-                        self.bld.env, proc_env, force_no_valgrind=True)
-
 def check_shell(bld):
     if ('NS3_MODULE_PATH' not in os.environ) or ('NS3_EXECUTABLE_PATH' not in os.environ):
         return