build: CMake refactoring and fixes

Includes:
- fix int64x64 parsing order, remove cached entries in macros-and-definitions and in the docs
- update launch.json scratch names
- add a ctest entry per executable
- forward POSIX signal in ns3 (to get segmentation fault)
- prioritize Ninja generator instead of Makefiles
- add tests for unused utils source files
- remove dummy file and add tests to check for unused source files
- add missing examples and clean up unnecessary definitions
- missing feature entry for LTE used by pybindgen
- refactor CMake related filenames
- fix python libraries and include directories bindings
- fix brite example name
- Keep C++ compiler and flags when refreshing
- Disable precompiled headers when Ccache is found
- Mark find_external_library headers as advanced
- consolidate auxiliary files: build-status.py, _cache.py and .lock-waf_sys.platform_build files are merged into .lock-ns3_sys.platform_build
- scan .cc sources used in bindings and update docs

doc/manual/source/python.rst

@@ -96,6 +96,12 @@ Here is some example code that is written in Python and that runs |ns3|, which i
 Running Python Scripts
 **********************
 
+First, we need to enable the build of python bindings:
+
+.. sourcecode:: bash
+
+  $ ./ns3 configure --enable-python-bindings
+
 ns3 contains some options that automatically update the python path to find the ns3 module.  To run example programs, there are two ways to use ns3 to take care of this.  One is to run a ns3 shell; e.g.:
 
 .. sourcecode:: bash
@@ -103,17 +109,15 @@ ns3 contains some options that automatically update the python path to find the
   $ ./ns3 shell
   $ python examples/wireless/mixed-wireless.py
 
-and the other is to use the --pyrun option to ns3:
+and the other is to use the 'run' option to ns3:
 
 .. sourcecode:: bash
 
   $ ./ns3 run examples/wireless/mixed-wireless.py
 
-As of ns-3.30, a --pyrun-no-build option was added to allow the running of
-a program without invoking a project rebuild.  This option may be useful
-to improve execution time when running the same program repeatedly but with
-different arguments, such as from scripts. It can be used in place of
---pyrun such as:
+Use the ``--no-build`` option to run the program without invoking a project rebuild.
+This option may be useful to improve execution time when running the same program
+repeatedly but with different arguments, such as from scripts.
 
 .. sourcecode:: bash
 
@@ -251,13 +255,7 @@ If something goes wrong with compiling Python bindings and you just want to igno
 
 .. sourcecode:: bash
 
-  $ ./ns3 configure --disable-python ...
-
-To add support for modular bindings to an existing or new |ns3| module, simply add the following line to its wscript build() function:
-
-::
-
-    bld.ns3_python_bindings()
+  $ ./ns3 configure --disable-python-bindings ...
 
 One must also provide the bindings files (usually by running the scanning
 framework).
@@ -494,14 +492,14 @@ To re-scan a module:
 .. sourcecode:: bash
 
     $ cd source/ns-3-dev
-    $ ./ns3 --apiscan=wifi
+    $ ./ns3 build wifi-apiscan
 
 To re-scan all modules:
 
 .. sourcecode:: bash
 
     $ cd source/ns-3-dev
-    $ ./ns3 --apiscan=all
+    $ ./ns3 apiscan-all
 
 Generating bindings on MacOS
 ############################
@@ -520,7 +518,7 @@ The ``src/<module>/bindings`` directory may contain the following files, some of
 * ``modulegen__gcc_ILP32.py``: this is a scanned file, DO NOT TOUCH.  Scanned API definitions for the GCC, ILP32 architecture (32-bit)
 * ``modulegen_customizations.py``: you may optionally add this file in order to customize the pybindgen code generation
 * ``scan-header.h``: you may optionally add this file to customize what header file is scanned for the module.  Basically this file is scanned instead of ns3/<module>-module.h.  Typically, the first statement is #include "ns3/<module>-module.h", plus some other stuff to force template instantiations;
-* ``module_helpers.cc``: you may add additional files, such as this, to be linked to python extension module, but they have to be registered in the wscript. Look at src/core/wscript for an example of how to do so;
+* ``module_helpers.cc``: you may add additional files, such as this, to be linked to python extension module. They will be automatically scanned;
 * ``<module>.py``: if this file exists, it becomes the "frontend" python module for the ns3 module, and the extension module (.so file) becomes _<module>.so instead of <module>.so.  The <module>.py file has to import all symbols from the module _<module> (this is more tricky than it sounds, see src/core/bindings/core.py for an example), and then can add some additional pure-python definitions.   
 
 Historical Information