deploy-ng: Look for correct platform suffixes for Python extension modules when cross-building

Note: We still need to supply suffixes for macOS. Also, Linux suffixes
are based on suffixes on my system (Arch, Python3) and will likely need
to be tweaked.

direct/src/showutil/FreezeTool.py

@@ -717,6 +717,28 @@ class Freezer:
                 if path:
                     modulefinder.AddPackagePath(moduleName, path[0])
 
+        # Suffix/extension for Python C extension modules
+        if self.platform == PandaSystem.getPlatform():
+            self.moduleSuffixes = imp.get_suffixes()
+        else:
+            self.moduleSuffixes = [('.py', 'r', 1), ('.pyc', 'rb', 2)]
+            if 'linux' in self.platform:
+                self.moduleSuffixes += [
+                    ('.cpython-{0}{1}m-x86_64-linux-gnu.so'.format(*sys.version_info), 'rb', 3),
+                    ('.cpython-{0}{1}m-i686-linux-gnu.so'.format(*sys.version_info), 'rb', 3),
+                    ('.abi{}.so'.format(sys.version_info[0]), 'rb', 3),
+                    ('.so', 'rb', 3),
+                ]
+            elif 'win' in self.platform:
+                self.moduleSuffixes += [
+                    ('.cp{0}{1}-win_amd64.pyd'.format(*sys.version_info), 'rb', 3),
+                    ('.cp{0}{1}-win32.pyd'.format(*sys.version_info), 'rb', 3),
+                    ('.dll', 'rb', 3),
+                ]
+            else:
+                print("Unknown platform %s" % (self.platform))
+                self.moduleSuffixes = imp.get_suffixes()
+
     def excludeFrom(self, freezer):
         """ Excludes all modules that have already been processed by
         the indicated FreezeTool.  This is equivalent to passing the
@@ -966,7 +988,7 @@ class Freezer:
             else:
                 includes.append(mdef)
 
-        self.mf = PandaModuleFinder(excludes = list(excludeDict.keys()))
+        self.mf = PandaModuleFinder(excludes = list(excludeDict.keys()), suffixes=self.moduleSuffixes)
 
         # Attempt to import the explicit modules into the modulefinder.
 

direct/src/showutil/dist.py

@@ -100,7 +100,7 @@ class build(distutils.command.build.build):
             freezer_extras = set()
             freezer_modules = set()
             for app in self.distribution.applications:
-                freezer = FreezeTool.Freezer()
+                freezer = FreezeTool.Freezer(platform=platform)
                 freezer.addModule('__main__', filename=app.scriptname)
                 for exmod in self.distribution.exclude_modules:
                     freezer.excludeModule(exmod)
@@ -226,7 +226,10 @@ class bdist_panda3d(distutils.core.Command):
         pass
 
     def run(self):
-        platforms = [p3d.PandaSystem.get_platform()]
+        if not self.distribution.deploy_platforms:
+            platforms = [p3d.PandaSystem.get_platform()]
+        else:
+            platforms = self.distribution.deploy_platforms
         build_base = os.path.join(os.getcwd(), 'build')
 
         self.run_command("build")