diff --git a/dtool/src/cppparser/cppPreprocessor.cxx b/dtool/src/cppparser/cppPreprocessor.cxx
index 52c758acd6..cbb7174239 100644
--- a/dtool/src/cppparser/cppPreprocessor.cxx
+++ b/dtool/src/cppparser/cppPreprocessor.cxx
@@ -687,7 +687,7 @@ push_string(const string &input, bool lock_position) {
 //               string and return the new string.
 ////////////////////////////////////////////////////////////////////
 string CPPPreprocessor::
-expand_manifests(const string &input_expr) {
+expand_manifests(const string &input_expr, bool expand_undefined) {
   // Get a copy of the expression string we can modify.
   string expr = input_expr;
 
@@ -722,6 +722,10 @@ expand_manifests(const string &input_expr) {
               expand_manifest_inline(expr, q, p, (*mi).second);
               manifest_found = true;
             }
+          } else if (expand_undefined && ident != "true" && ident != "false") {
+            // It is not found.  Expand it to 0.
+            expr = expr.substr(0, q) + "0" + expr.substr(p);
+            p = q + 1;
           }
         }
       } else {
@@ -751,7 +755,7 @@ expand_manifests(const string &input_expr) {
 CPPExpression *CPPPreprocessor::
 parse_expr(const string &input_expr, CPPScope *current_scope,
            CPPScope *global_scope) {
-  string expr = expand_manifests(input_expr);
+  string expr = expand_manifests(input_expr, true);
 
   CPPExpressionParser ep(current_scope, global_scope);
   ep._verbose = 0;
@@ -1380,7 +1384,7 @@ handle_include_directive(const string &args, int first_line,
   // might not filter out quotes and angle brackets properly, we'll
   // only expand manifests if we don't begin with a quote or bracket.
   if (!expr.empty() && (expr[0] != '"' && expr[0] != '<')) {
-    expr = expand_manifests(expr);
+    expr = expand_manifests(expr, false);
   }
 
   if (!expr.empty()) {
diff --git a/dtool/src/cppparser/cppPreprocessor.h b/dtool/src/cppparser/cppPreprocessor.h
index 571ef0598b..9aedcb24de 100644
--- a/dtool/src/cppparser/cppPreprocessor.h
+++ b/dtool/src/cppparser/cppPreprocessor.h
@@ -106,7 +106,7 @@ protected:
   bool push_file(const CPPFile &file);
   bool push_string(const string &input, bool lock_position);
 
-  string expand_manifests(const string &input_expr);
+  string expand_manifests(const string &input_expr, bool expand_undefined);
   CPPExpression *parse_expr(const string &expr, CPPScope *current_scope,
                             CPPScope *global_scope);
 
diff --git a/dtool/src/parser-inc/stdtypedefs.h b/dtool/src/parser-inc/stdtypedefs.h
index 345eda1fd0..99280ebb4f 100644
--- a/dtool/src/parser-inc/stdtypedefs.h
+++ b/dtool/src/parser-inc/stdtypedefs.h
@@ -39,10 +39,13 @@ typedef unsigned short ushort;
 typedef unsigned char uchar;
 
 #ifdef __cplusplus
-#define NULL 0
+#define NULL 0L
 #else
 #define NULL ((void *)0)
 #endif
 
-#endif
+// One day, we might extend interrogate to be able to parse this,
+// but we currently don't need it.
+#define alignas(x)
 
+#endif
diff --git a/makepanda/makepanda.py b/makepanda/makepanda.py
index b7ac3cbc4a..d7bc6e723d 100755
--- a/makepanda/makepanda.py
+++ b/makepanda/makepanda.py
@@ -1020,7 +1020,6 @@ def CompileCxx(obj,src,opts):
                 if (opt=="ALWAYS") or (opt in opts): cmd += " /I" + BracketNameWithQuotes(dir)
             for (opt,var,val) in DEFSYMBOLS:
                 if (opt=="ALWAYS") or (opt in opts): cmd += " /D" + var + "=" + val
-            if (opts.count('NOFLOATWARN')): cmd += ' /wd4244 /wd4305'
             if (opts.count('MSFORSCOPE')): cmd += ' /Zc:forScope-'
 
             if (optlevel==1): cmd += " /MDd /Zi /RTCs /GS"
@@ -1070,7 +1069,6 @@ def CompileCxx(obj,src,opts):
                 if (opt=="ALWAYS") or (opt in opts): cmd += " /I" + BracketNameWithQuotes(dir)
             for (opt,var,val) in DEFSYMBOLS:
                 if (opt=="ALWAYS") or (opt in opts): cmd += " /D" + var + "=" + val
-            if (opts.count('NOFLOATWARN')): cmd += ' /wd4244 /wd4305'
             if (opts.count('MSFORSCOPE')):  cmd += ' /Zc:forScope-'
 
             if (optlevel==1): cmd += " /MDd /Zi /RTCs /GS"
@@ -1339,14 +1337,15 @@ def CompileIgate(woutd,wsrc,opts):
         cmd = 'interrogate'
 
     cmd += ' -srcdir %s -I%s -Dvolatile -Dmutable' % (srcdir, srcdir)
+    cmd += ' -DCPPPARSER -D__STDC__=1 -D__cplusplus=201103L'
     if (COMPILER=="MSVC"):
-        cmd += ' -DCPPPARSER -D__STDC__=1 -D__cplusplus -D__inline -D_X86_ -DWIN32_VC -DWIN32 -D_WIN32'
+        cmd += ' -D__inline -D_X86_ -DWIN32_VC -DWIN32 -D_WIN32'
         if GetTargetArch() == 'x64':
             cmd += ' -DWIN64_VC -DWIN64 -D_WIN64'
         # NOTE: this 1600 value is the version number for VC2010.
-        cmd += ' -D_MSC_VER=1600 -D"_declspec(param)=" -D_near -D_far -D__near -D__far -D__stdcall'
+        cmd += ' -D_MSC_VER=1600 -D"__declspec(param)=" -D__cdecl -D_near -D_far -D__near -D__far -D__stdcall'
     if (COMPILER=="GCC"):
-        cmd += ' -DCPPPARSER -D__STDC__=1 -D__cplusplus -D__inline -D__const=const -D__attribute__\(x\)='
+        cmd += ' -D__inline -D__const=const -D__attribute__\(x\)='
         if GetTargetArch() in ("x86_64", "amd64"):
             cmd += ' -D_LP64'
         else: