diff --git a/Mac/Compat/getbootvol.c b/Mac/Compat/getbootvol.c
index 8f5d28c0b30..df450c652ca 100644
--- a/Mac/Compat/getbootvol.c
+++ b/Mac/Compat/getbootvol.c
@@ -5,7 +5,7 @@
 #include "macdefs.h"
 
 char *
-getbootvol()
+getbootvol(void)
 {
 	short vrefnum;
 	static unsigned char name[32];
diff --git a/Mac/Compat/getwd.c b/Mac/Compat/getwd.c
index 27f68a24faa..1487fb0e7f2 100644
--- a/Mac/Compat/getwd.c
+++ b/Mac/Compat/getwd.c
@@ -32,8 +32,7 @@
 #define ROOTID 2 /* Root directory ID */
 
 char *
-getwd(cwd)
-	char *cwd;
+getwd(char *cwd)
 {
 	/* Universal parameter block. */
 	union {
diff --git a/Mac/Compat/macstat.h b/Mac/Compat/macstat.h
index 64ace4e7f40..d6cad851942 100644
--- a/Mac/Compat/macstat.h
+++ b/Mac/Compat/macstat.h
@@ -27,6 +27,7 @@ struct macstat {
 #define S_IWRITE   0200
 #define S_IEXEC    0100
 
+extern int macstat(char *, struct macstat *);
 /* To stop inclusion of MWerks header: */
 #ifndef _STAT
 #define _STAT
diff --git a/Mac/Compat/sync.c b/Mac/Compat/sync.c
index a6487e12ca8..944ba2358d5 100644
--- a/Mac/Compat/sync.c
+++ b/Mac/Compat/sync.c
@@ -6,7 +6,7 @@
 #include "macdefs.h"
 
 int
-sync()
+sync(void)
 {
 	if (FlushVol((StringPtr)0, 0) == noErr)
 		return 0;
diff --git a/Mac/Include/macdefs.h b/Mac/Include/macdefs.h
index 9cc3ae19403..8898b4973da 100644
--- a/Mac/Include/macdefs.h
+++ b/Mac/Include/macdefs.h
@@ -15,8 +15,10 @@
 #endif
 
 /* We may be able to use a std routine in think, don't know */
-unsigned char *Pstring(char *);
-
+extern unsigned char *Pstring(char *);
+extern char *getbootvol(void);
+extern char *getwd(char *);
+extern int sync(void);
 
 /* Universal constants: */
 #define MAXPATH 256
diff --git a/Mac/Include/macglue.h b/Mac/Include/macglue.h
index f96b96fcad1..5767368bda8 100644
--- a/Mac/Include/macglue.h
+++ b/Mac/Include/macglue.h
@@ -81,6 +81,7 @@ void PyMac_GetSchedParams(PyMacSchedParams *);	/* Get schedulers params */
 void PyMac_SetSchedParams(PyMacSchedParams *);	/* Set schedulers params */
 PyObject *PyErr_Mac(PyObject *, int);		/* Exception with a mac error */
 PyObject *PyMac_Error(OSErr);			/* Uses PyMac_GetOSErrException */
+int PyOS_CheckStack(void);		/* Check that we aren't overflowing our stack */
 int PyMac_DoYield(int, int);	/* Yield cpu. First arg is maxtime, second ok to call python */
 int PyMac_HandleEvent(EventRecord *);	/* Handle one event, possibly in Python */
 void PyMac_HandleEventIntern(EventRecord *); /* Handle one event internal only */
@@ -133,8 +134,22 @@ short PyMac_OpenPrefFile(void);			/* From macgetpath.c, open and return preferen
 
 /* From macfiletype.c: */
 
-long getfiletype(char *);			/* Get file type */
-int setfiletype(char *, long, long);		/* Set file creator and type */
+long PyMac_getfiletype(char *);			/* Get file type */
+int PyMac_setfiletype(char *, long, long);		/* Set file creator and type */
+
+/* from macmain.c: */
+void PyMac_Exit(int);
+void PyMac_InitApplication(void);
+#ifdef USE_MAC_APPLET_SUPPORT
+void PyMac_InitApplet(void);
+#endif
+
+/* from macgetargv: */
+OSErr PyMac_init_process_location(void);
+#ifndef HAVE_STRDUP
+char *	strdup(const char *str);
+#endif
+
 #ifdef __cplusplus
 	}
 #endif
diff --git a/Mac/Modules/macfsmodule.c b/Mac/Modules/macfsmodule.c
index bdc1263cdb7..048b243023e 100644
--- a/Mac/Modules/macfsmodule.c
+++ b/Mac/Modules/macfsmodule.c
@@ -34,6 +34,9 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include "getapplbycreator.h"
 
+/* Should this be in macglue.h? */
+extern FSSpec *mfs_GetFSSpecFSSpec(PyObject *);
+
 static PyObject *ErrorObject;
 
 /* ----------------------------------------------------- */
@@ -174,9 +177,8 @@ mfsa_getattr(self, name)
 	return Py_FindMethod(mfsa_methods, (PyObject *)self, name);
 }
 
-mfsaobject *
-newmfsaobject(alias)
-	AliasHandle alias;
+static mfsaobject *
+newmfsaobject(AliasHandle alias)
 {
 	mfsaobject *self;
 
@@ -334,8 +336,7 @@ static PyTypeObject Mfsitype = {
 ** object is a python fsspec object, else NULL
 */
 FSSpec *
-mfs_GetFSSpecFSSpec(self)
-	PyObject *self;
+mfs_GetFSSpecFSSpec(PyObject *self)
 {
 	if ( is_mfssobject(self) )
 		return &((mfssobject *)self)->fsspec;
diff --git a/Mac/Modules/macspeechmodule.c b/Mac/Modules/macspeechmodule.c
index accb7b28bbb..a6fbddd645e 100644
--- a/Mac/Modules/macspeechmodule.c
+++ b/Mac/Modules/macspeechmodule.c
@@ -24,6 +24,7 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 
 #include "Python.h"
+#include "macglue.h"
 
 #include <Gestalt.h>
 #include "Speech.h"
diff --git a/Mac/Python/macapplication.c b/Mac/Python/macapplication.c
index 0fe1c7021f3..3923af204b2 100644
--- a/Mac/Python/macapplication.c
+++ b/Mac/Python/macapplication.c
@@ -31,11 +31,13 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #pragma lib_export on
 #endif
 
-extern void PyMac_InitApplet();
+extern void PyMac_InitApplication(void);
 #ifdef USE_MAC_APPLET_SUPPORT
-extern void PyMac_InitApplication();
+extern void PyMac_InitApplet(void);
 #endif /* USE_MAC_APPLET_SUPPORT */
 
+/* From the MSL runtime: */
+extern void __initialize(void);
 
 /*
 ** Alternative initialization entry point for some very special cases.
diff --git a/Mac/Python/macgetargv.c b/Mac/Python/macgetargv.c
index 1eb4a54b770..b4a3ec6c87d 100644
--- a/Mac/Python/macgetargv.c
+++ b/Mac/Python/macgetargv.c
@@ -53,15 +53,16 @@ static int applocation_inited;
 /* Duplicate a string to the heap. We also export this since it isn't standard
 ** and others use it
 */
-
+#ifndef HAVE_STRDUP
 char *
-strdup(char *src)
+strdup(const char *src)
 {
 	char *dst = malloc(strlen(src) + 1);
 	if (dst)
 		strcpy(dst, src);
 	return dst;
 }
+#endif
 
 /* Initialize FSSpec and full name of current application */
 
diff --git a/Mac/Python/macgetcompiler.c b/Mac/Python/macgetcompiler.c
index 226fa29e851..39f3a2b1911 100644
--- a/Mac/Python/macgetcompiler.c
+++ b/Mac/Python/macgetcompiler.c
@@ -32,6 +32,7 @@ PERFORMANCE OF THIS SOFTWARE.
 /* Return a string representing the compiler name */
 
 #include "config.h"
+#include "Python.h"
 
 #ifdef __MWERKS__
 #ifdef USE_GUSI1
@@ -75,8 +76,8 @@ PERFORMANCE OF THIS SOFTWARE.
 #endif
 #endif
 
-char *
-Py_GetCompiler()
+const char *
+Py_GetCompiler(void)
 {
 	return COMPILER;
 }
diff --git a/Mac/Python/macgetpath.c b/Mac/Python/macgetpath.c
index bc957cc7c43..c180d1fa466 100644
--- a/Mac/Python/macgetpath.c
+++ b/Mac/Python/macgetpath.c
@@ -33,6 +33,9 @@ PERFORMANCE OF THIS SOFTWARE.
 #include "osdefs.h"
 #include "macglue.h"
 #include "pythonresources.h"
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
 
 
 /* Return the initial python search path.  This is called once from
@@ -58,6 +61,10 @@ PERFORMANCE OF THIS SOFTWARE.
 #include <GUSI.h>
 #endif
 
+#ifndef USE_BUILTIN_PATH
+staticforward char *PyMac_GetPythonPath();
+#endif
+
 #define PYTHONPATH "\
 :\n\
 :Lib\n\
@@ -143,9 +150,6 @@ Py_GetPath()
 	char *p, *endp;
 	int newlen;
 	char *curwd;
-#ifndef USE_BUILTIN_PATH
-	staticforward char *PyMac_GetPythonPath();
-#endif
 	
 	if ( pythonpath ) return pythonpath;
 #ifndef USE_BUILTIN_PATH
@@ -294,7 +298,7 @@ PyMac_GetPythonDir()
 
 #ifndef USE_BUILTIN_PATH
 char *
-PyMac_GetPythonPath()
+PyMac_GetPythonPath(void)
 {
 	short oldrh, prefrh = -1;
 	char *rv;
diff --git a/Mac/Python/macgetplatform.c b/Mac/Python/macgetplatform.c
index cbfc890fdef..3640d760ee6 100644
--- a/Mac/Python/macgetplatform.c
+++ b/Mac/Python/macgetplatform.c
@@ -29,8 +29,10 @@ PERFORMANCE OF THIS SOFTWARE.
 
 ******************************************************************/
 
-char *
-Py_GetPlatform()
+#include "Python.h"
+
+const char *
+Py_GetPlatform(void)
 {
 	return "mac";
 }
diff --git a/Mac/Python/macglue.c b/Mac/Python/macglue.c
index 1266b59c469..607f4bbfcfe 100644
--- a/Mac/Python/macglue.c
+++ b/Mac/Python/macglue.c
@@ -63,7 +63,19 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <TextUtils.h>
 #ifdef __MWERKS__
 #include <SIOUX.h>
+extern void SIOUXSetupMenus(void);
+extern void SIOUXDoAboutBox(void);
 #endif
+#ifdef USE_GUSI
+/* Functions we redefine because they're in obscure libraries */
+extern void SpinCursor(short x);
+extern void RotateCursor(short x);
+extern pascal void PLstrcpy(unsigned char *, unsigned char *);
+extern pascal int PLstrcmp(unsigned char *, unsigned char *);
+extern pascal unsigned char *PLstrrchr(unsigned char *, unsigned char);
+
+#endif
+
 #ifdef USE_GUSI1
 #include <TFileSpec.h> /* For Path2FSSpec */
 #include <GUSI.h>
@@ -103,7 +115,7 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #define fnfErr -43
 
 /* Declared in macfsmodule.c: */
-extern FSSpec *mfs_GetFSSpecFSSpec();
+extern FSSpec *mfs_GetFSSpecFSSpec(PyObject *);
 extern PyObject *newmfssobject(FSSpec *);
 
 /* Interrupt code variables: */
@@ -246,15 +258,13 @@ PyMac_StopGUSISpin() {
 ** StdCLib. Moreover, that implementation is broken under cfm68k...
 */
 pascal void
-PLstrcpy(to, fr)
-	unsigned char *to, *fr;
+PLstrcpy(unsigned char *to, unsigned char *fr)
 {
 	memcpy(to, fr, fr[0]+1);
 }
 
 pascal int
-PLstrcmp(s1, s2)
-	unsigned char *s1, *s2;
+PLstrcmp(unsigned char *s1, unsigned char *s2)
 {
 	int res;
 	int l = s1[0] < s2[0] ? s1[0] : s2[0];
@@ -272,9 +282,7 @@ PLstrcmp(s1, s2)
 }
 
 pascal unsigned char *
-PLstrrchr(str, chr)
-	unsigned char *str;
-	unsigned char chr;
+PLstrrchr(unsigned char *str, unsigned char chr)
 {
 	unsigned char *ptr = 0;
 	unsigned char *p;
@@ -457,8 +465,8 @@ PyOS_InterruptOccurred()
 	return interrupted;
 }
 /* Check whether we are in the foreground */
-int
-PyMac_InForeground()
+static int
+PyMac_InForeground(void)
 {
 	static ProcessSerialNumber ours;
 	static inited;
diff --git a/Mac/Python/macguesstabsize.c b/Mac/Python/macguesstabsize.c
index 64a6ad7c6e7..482f43df19e 100644
--- a/Mac/Python/macguesstabsize.c
+++ b/Mac/Python/macguesstabsize.c
@@ -37,7 +37,7 @@ PERFORMANCE OF THIS SOFTWARE.
 #include <string.h>
 
 /* Interface used by parsetok.c */
-
+#error
 guesstabsize(path)
 	char *path;
 {
diff --git a/Mac/Python/macimport.c b/Mac/Python/macimport.c
index 1b3b994fa3d..08065361a53 100644
--- a/Mac/Python/macimport.c
+++ b/Mac/Python/macimport.c
@@ -413,7 +413,9 @@ PyMac_FindModuleExtension(char *buf, size_t *lenp, char *module)
 	unsigned char fnbuf[64];
 	int modnamelen = strlen(module);
 	FSSpec fss;
+#ifdef USE_GUSI1
 	FInfo finfo;
+#endif
 	short refnum;
 	long dirid;
 	
diff --git a/Mac/Python/macmain.c b/Mac/Python/macmain.c
index 8b2a1fd67c9..e3e9615b861 100644
--- a/Mac/Python/macmain.c
+++ b/Mac/Python/macmain.c
@@ -44,6 +44,7 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #ifdef __MWERKS__
 #include <SIOUX.h>
 #define USE_SIOUX
+extern int ccommand(char ***);
 #if __profile__ == 1
 #include <profiler.h>
 #endif
@@ -549,9 +550,7 @@ Py_GetProgramFullPath()
    This is rare, but it is needed by the secureware extension. */
 
 void
-Py_GetArgcArgv(argc,argv)
-	int *argc;
-	char ***argv;
+Py_GetArgcArgv(int *argc,char ***argv)
 {
 	*argc = orig_argc;
 	*argv = orig_argv;
diff --git a/Mac/Python/macsetfiletype.c b/Mac/Python/macsetfiletype.c
index c4b114fff72..b2d9531e5f4 100644
--- a/Mac/Python/macsetfiletype.c
+++ b/Mac/Python/macsetfiletype.c
@@ -34,10 +34,12 @@ PERFORMANCE OF THIS SOFTWARE.
  *
  */
  
+#include "Python.h"
+#include "macglue.h"
 #include "macdefs.h"
 
 int
-setfiletype(name, creator, type)
+PyMac_setfiletype(name, creator, type)
 char *name;
 long creator, type;
 {
@@ -56,7 +58,7 @@ long creator, type;
 }
 
 long
-getfiletype(name)
+PyMac_getfiletype(name)
 char *name;
 {
 	FInfo info;
diff --git a/Mac/mwerks/malloc/malloc.c b/Mac/mwerks/malloc/malloc.c
index 7d0fb6c6fe4..38bd32a857b 100644
--- a/Mac/mwerks/malloc/malloc.c
+++ b/Mac/mwerks/malloc/malloc.c
@@ -78,7 +78,9 @@ typedef u_long caddr_t;
 #include <stdlib.h>
 #include <string.h>
 
+#ifndef NULL
 #define	NULL 0
+#endif
 
 static void morecore();