[CMake] Fix dependencies for generating gparams_register_modules.cpp.

Previously CMake was not aware of which headers files the generation
of `gparams_register_modules.cpp` depended on. Consequently this could result
in broken incremental builds if

* Existing headers that declared module description/parameters change.
* New headers are added that declare module description/parameters.
* `.pyg` files that generate header files that declare module
  description/parameters change

Now the `z3_add_component()` CMake function has been modifed so that

* All header files that are generated from `.pyg` files are added as
dependencies and are scanned from module description/parameter
declarations. This implicit dependency of `gparams_register_modules.cpp`
depending on other generated header files seems unnecessary complex. We
should revisit this design decision once the Python/Makefile build
system is deprecated.

* The function now takes an optional `EXTRA_REGISTER_MODULE_HEADERS`
argument which allows the headers that declare module
description/paramters to be explicitly listed.

With this information CMake will now regenerate `gparams_register_modules.cpp`
correctly.

This required the `mk_gparams_register_modules_internal()` function to be
changed to take a list of header files rather than a list of component
source directories. The two consumers (CMake and Python/Makefile build
systems) of this function have been modified to work with this change.

This partially fixes #1030.

scripts/mk_genfile_common.py

@@ -587,7 +587,7 @@ def mk_def_file_internal(defname, dll_name, export_header_files):
 ###############################################################################
 # Functions for generating ``gparams_register_modules.cpp``
 ###############################################################################
-def mk_gparams_register_modules_internal(component_src_dirs, path):
+def mk_gparams_register_modules_internal(h_files_full_path, path):
     """
         Generate a ``gparams_register_modules.cpp`` file in the directory ``path``.
         Returns the path to the generated file.
@@ -600,7 +600,7 @@ def mk_gparams_register_modules_internal(component_src_dirs, path):
 
         This procedure is invoked by gparams::init()
     """
-    assert isinstance(component_src_dirs, list)
+    assert isinstance(h_files_full_path, list)
     assert check_dir_exists(path)
     cmds = []    
     mod_cmds = []
@@ -612,11 +612,6 @@ def mk_gparams_register_modules_internal(component_src_dirs, path):
     reg_pat = re.compile('[ \t]*REG_PARAMS\(\'([^\']*)\'\)')
     reg_mod_pat = re.compile('[ \t]*REG_MODULE_PARAMS\(\'([^\']*)\', *\'([^\']*)\'\)')
     reg_mod_descr_pat = re.compile('[ \t]*REG_MODULE_DESCRIPTION\(\'([^\']*)\', *\'([^\']*)\'\)')
-    h_files_full_path = []
-    for component_src_dir in component_src_dirs:
-        h_files = filter(lambda f: f.endswith('.h') or f.endswith('.hpp'), os.listdir(component_src_dir))
-        h_files = list(map(lambda p: os.path.join(component_src_dir, p), h_files))
-        h_files_full_path.extend(h_files)
     for h_file in sorted_headers_by_component(h_files_full_path):
         added_include = False
         with open(h_file, 'r') as fin:

scripts/mk_gparams_register_modules_cpp.py

@@ -1,10 +1,8 @@
 #!/usr/bin/env python
 """
-Determines the available global parameters
-in header files in the list of source directions
-and generates a ``gparams_register_modules.cpp`` file in
-the destination directory that defines a function
-``void gparams_register_modules()``.
+Determines the available global parameters from a list of header files and
+generates a ``gparams_register_modules.cpp`` file in the destination directory
+that defines a function ``void gparams_register_modules()``.
 """
 import mk_genfile_common
 import argparse
@@ -16,19 +14,22 @@ def main(args):
     logging.basicConfig(level=logging.INFO)
     parser = argparse.ArgumentParser(description=__doc__)
     parser.add_argument("destination_dir", help="destination directory")
-    parser.add_argument("source_dirs", nargs="+",
-                        help="One or more source directories to search")
+    parser.add_argument("header_files", nargs="+",
+                        help="One or more header files to parse")
     pargs = parser.parse_args(args)
 
     if not mk_genfile_common.check_dir_exists(pargs.destination_dir):
         return 1
 
-    for source_dir in pargs.source_dirs:
-        if not mk_genfile_common.check_dir_exists(source_dir):
-            return 1
+    if not mk_genfile_common.check_files_exist(pargs.header_files):
+        return 1
+
+    h_files_full_path = []
+    for header_file in pargs.header_files:
+        h_files_full_path.append(os.path.abspath(header_file))
 
     output = mk_genfile_common.mk_gparams_register_modules_internal(
-        pargs.source_dirs,
+        h_files_full_path,
         pargs.destination_dir
     )
     logging.info('Generated "{}"'.format(output))

scripts/mk_util.py

@@ -2763,7 +2763,8 @@ def mk_gparams_register_modules(cnames, path):
     for cname in cnames:
         c = get_component(cname)
         component_src_dirs.append(c.src_dir)
-    generated_file = mk_genfile_common.mk_gparams_register_modules_internal(component_src_dirs, path)
+    h_files_full_path = get_header_files_for_components(component_src_dirs)
+    generated_file = mk_genfile_common.mk_gparams_register_modules_internal(h_files_full_path, path)
     if VERBOSE:
         print("Generated '{}'".format(generated_file))