direct: fix various syntax warnings in Python 3.8

direct/src/actor/Actor.py

@@ -2507,7 +2507,7 @@ class Actor(DirectObject, NodePath):
         else:
             animNames = [animName]
         for animName in animNames:
-            if animName is 'nothing':
+            if animName == 'nothing':
                 continue
             thisAnim = ''
             totalEffect = 0.

direct/src/directscripts/gendocs.py

@@ -56,9 +56,9 @@ import os, sys, parser, symbol, token, re
 #
 ########################################################################
 
-SECHEADER = re.compile("^[A-Z][a-z]+\s*:")
-JUNKHEADER = re.compile("^((Function)|(Access))\s*:")
-IMPORTSTAR = re.compile("^from\s+([a-zA-Z0-9_.]+)\s+import\s+[*]\s*$")
+SECHEADER = re.compile("^[A-Z][a-z]+\\s*:")
+JUNKHEADER = re.compile("^((Function)|(Access))\\s*:")
+IMPORTSTAR = re.compile("^from\\s+([a-zA-Z0-9_.]+)\\s+import\\s+[*]\\s*$")
 IDENTIFIER = re.compile("[a-zA-Z0-9_]+")
 FILEHEADER = re.compile(
 r"""^// Filename: [a-zA-Z.]+

direct/src/dist/FreezeTool.py

@@ -210,15 +210,15 @@ class CompilationEnvironment:
             if ('MAKEPANDA' in os.environ):
                 self.compileObjExe = 'cl /wd4996 /Fo%(basename)s.obj /nologo /c %(MD)s /Zi /O2 /Ob2 /EHsc /Zm300 /W3 /I"%(pythonIPath)s" %(filename)s'
                 self.compileObjDll = self.compileObjExe
-                self.linkExe = 'link /nologo /MAP:NUL /FIXED:NO /OPT:REF /STACK:4194304 /INCREMENTAL:NO /LIBPATH:"%(python)s\libs"  /out:%(basename)s.exe %(basename)s.obj'
-                self.linkDll = 'link /nologo /DLL /MAP:NUL /FIXED:NO /OPT:REF /INCREMENTAL:NO /LIBPATH:"%(python)s\libs"  /out:%(basename)s%(dllext)s.pyd %(basename)s.obj'
+                self.linkExe = 'link /nologo /MAP:NUL /FIXED:NO /OPT:REF /STACK:4194304 /INCREMENTAL:NO /LIBPATH:"%(python)s\\libs"  /out:%(basename)s.exe %(basename)s.obj'
+                self.linkDll = 'link /nologo /DLL /MAP:NUL /FIXED:NO /OPT:REF /INCREMENTAL:NO /LIBPATH:"%(python)s\\libs"  /out:%(basename)s%(dllext)s.pyd %(basename)s.obj'
             else:
                 os.environ['PATH'] += ';' + self.MSVC + '\\bin' + self.suffix64 + ';' + self.MSVC + '\\Common7\\IDE;' + self.PSDK + '\\bin'
 
-                self.compileObjExe = 'cl /wd4996 /Fo%(basename)s.obj /nologo /c %(MD)s /Zi /O2 /Ob2 /EHsc /Zm300 /W3 /I"%(pythonIPath)s" /I"%(PSDK)s\include" /I"%(MSVC)s\include" %(filename)s'
+                self.compileObjExe = 'cl /wd4996 /Fo%(basename)s.obj /nologo /c %(MD)s /Zi /O2 /Ob2 /EHsc /Zm300 /W3 /I"%(pythonIPath)s" /I"%(PSDK)s\\include" /I"%(MSVC)s\\include" %(filename)s'
                 self.compileObjDll = self.compileObjExe
-                self.linkExe = 'link /nologo /MAP:NUL /FIXED:NO /OPT:REF /STACK:4194304 /INCREMENTAL:NO /LIBPATH:"%(PSDK)s\lib" /LIBPATH:"%(MSVC)s\\lib%(suffix64)s" /LIBPATH:"%(python)s\libs"  /out:%(basename)s.exe %(basename)s.obj'
-                self.linkDll = 'link /nologo /DLL /MAP:NUL /FIXED:NO /OPT:REF /INCREMENTAL:NO /LIBPATH:"%(PSDK)s\lib" /LIBPATH:"%(MSVC)s\\lib%(suffix64)s" /LIBPATH:"%(python)s\libs"  /out:%(basename)s%(dllext)s.pyd %(basename)s.obj'
+                self.linkExe = 'link /nologo /MAP:NUL /FIXED:NO /OPT:REF /STACK:4194304 /INCREMENTAL:NO /LIBPATH:"%(PSDK)s\\lib" /LIBPATH:"%(MSVC)s\\lib%(suffix64)s" /LIBPATH:"%(python)s\\libs"  /out:%(basename)s.exe %(basename)s.obj'
+                self.linkDll = 'link /nologo /DLL /MAP:NUL /FIXED:NO /OPT:REF /INCREMENTAL:NO /LIBPATH:"%(PSDK)s\\lib" /LIBPATH:"%(MSVC)s\\lib%(suffix64)s" /LIBPATH:"%(python)s\\libs"  /out:%(basename)s%(dllext)s.pyd %(basename)s.obj'
 
         elif self.platform.startswith('osx_'):
             # OSX

direct/src/showbase/FindCtaPaths.py

@@ -21,7 +21,7 @@ def deCygwinify(path):
 
         dirs = path.split('/')
         if len(dirs) > 2 and len(dirs[1]) == 1:
-            path = '%s:\%s' % (dirs[1], '\\'.join(dirs[2:]))
+            path = '%s:\\%s' % (dirs[1], '\\'.join(dirs[2:]))
 
         else:
             # Otherwise, prepend $PANDA_ROOT and flip the slashes.

direct/src/showbase/PythonUtil.py

@@ -2513,7 +2513,7 @@ class AlphabetCounter:
         index = -1
         while True:
             curChar = self._curCounter[index]
-            if curChar is 'Z':
+            if curChar == 'Z':
                 nextChar = 'A'
                 carry = True
             else: