diff --git a/setup/BLDUTIL3.i b/setup/BLDUTIL3.c
similarity index 99%
rename from setup/BLDUTIL3.i
rename to setup/BLDUTIL3.c
index 29d5608..82e2b4e 100644
--- a/setup/BLDUTIL3.i
+++ b/setup/BLDUTIL3.c
@@ -17,6 +17,8 @@
 	BuiLD system UTILities part 3
 */
 
+#include "COREDEFS.h"
+
 
 #define src_d_name "src"
 #define cfg_d_name "cfg"
diff --git a/setup/BLDUTIL4.i b/setup/BLDUTIL4.c
similarity index 99%
rename from setup/BLDUTIL4.i
rename to setup/BLDUTIL4.c
index 3bf0aa9..f4cd143 100644
--- a/setup/BLDUTIL4.i
+++ b/setup/BLDUTIL4.c
@@ -17,6 +17,9 @@
 	BuiLD system UTILities part 4
 */
 
+#include "COREDEFS.h"
+#include "CNFGDLFT.h"
+
 LOCALPROC WriteOutDummyContents(void)
 {
 	WriteDestFileLn(
diff --git a/setup/CONFIGUR.i b/setup/CONFIGUR.i
deleted file mode 100644
index 34b0dec..0000000
--- a/setup/CONFIGUR.i
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
-	CONFIGUR.i
-*/
-
-/*
-	CONFIGURation file
-
-	see CNFGDLFT.i and CNFGOPTS.i for things
-		that can go here.
-*/
diff --git a/setup/COREDEFS.i b/setup/COREDEFS.h
similarity index 96%
rename from setup/COREDEFS.i
rename to setup/COREDEFS.h
index d3b5a24..4a41619 100644
--- a/setup/COREDEFS.i
+++ b/setup/COREDEFS.h
@@ -1,5 +1,5 @@
 /*
-	COREDEFS.i
+	COREDEFS.h
 	Copyright (C) 2018 Paul C. Pratt
 
 	You can redistribute this file and/or modify it under the terms
@@ -17,6 +17,8 @@
 	CORE DEFinitionS
 */
 
+#ifndef _COREDEFS_H
+#define _COREDEFS_H
 
 typedef unsigned long ui5b;
 typedef unsigned short ui4b;
@@ -88,3 +90,5 @@ typedef MyByte *MyPtr;
 #define EXPORTVAR static
 
 GLOBALVAR MyPtr pDt;
+
+#endif
diff --git a/setup/DFFILDEF.i b/setup/DFFILDEF.h
similarity index 100%
rename from setup/DFFILDEF.i
rename to setup/DFFILDEF.h
diff --git a/setup/GNBLDOPT.i b/setup/GNBLDOPT.c
similarity index 99%
rename from setup/GNBLDOPT.i
rename to setup/GNBLDOPT.c
index fa35150..f8dc66f 100644
--- a/setup/GNBLDOPT.i
+++ b/setup/GNBLDOPT.c
@@ -17,6 +17,8 @@
 	GeNeric BuiLD OPTions
 */
 
+#include "COREDEFS.h"
+
 /* --- default definitions for SPBASDEF --- */
 
 #ifndef MayUseSound
diff --git a/setup/SPBASDEF.i b/setup/SPBASDEF.h
similarity index 100%
rename from setup/SPBASDEF.i
rename to setup/SPBASDEF.h
diff --git a/setup/SPBLDOPT.i b/setup/SPBLDOPT.c
similarity index 99%
rename from setup/SPBLDOPT.i
rename to setup/SPBLDOPT.c
index ec252b4..8d9abef 100644
--- a/setup/SPBLDOPT.i
+++ b/setup/SPBLDOPT.c
@@ -17,6 +17,8 @@
 	program SPecific BuiLD OPTions
 */
 
+#include "COREDEFS.h"
+
 /* option: model */
 
 enum {
diff --git a/setup/SPCNFGAP.i b/setup/SPCNFGAP.c
similarity index 99%
rename from setup/SPCNFGAP.i
rename to setup/SPCNFGAP.c
index bbad0e9..fb60b89 100644
--- a/setup/SPCNFGAP.i
+++ b/setup/SPCNFGAP.c
@@ -20,6 +20,8 @@
 	only by platform specific code)
 */
 
+#include "COREDEFS.h"
+
 
 LOCALPROC WriteAppSpecificCNFGRAPIoptions(void)
 {
diff --git a/setup/SPCNFGGL.i b/setup/SPCNFGGL.c
similarity index 99%
rename from setup/SPCNFGGL.i
rename to setup/SPCNFGGL.c
index 6376639..0e6e1a2 100644
--- a/setup/SPCNFGGL.i
+++ b/setup/SPCNFGGL.c
@@ -17,6 +17,8 @@
 	program SPecific CoNFiGuration GLobals
 */
 
+#include "COREDEFS.h"
+
 LOCALPROC WriteAppSpecificCNFGGLOBoptions(void)
 {
 	WriteBlankLineToDestFile();
diff --git a/setup/SPFILDEF.i b/setup/SPFILDEF.c
similarity index 99%
rename from setup/SPFILDEF.i
rename to setup/SPFILDEF.c
index 91072ac..8fbb74a 100644
--- a/setup/SPFILDEF.i
+++ b/setup/SPFILDEF.c
@@ -17,7 +17,7 @@
 	program SPecific FILe DEFinitions
 */
 
-
+#include "COREDEFS.h"
 
 /* --- list of source files --- */
 
diff --git a/setup/SPOTHRCF.i b/setup/SPOTHRCF.c
similarity index 99%
rename from setup/SPOTHRCF.i
rename to setup/SPOTHRCF.c
index 34fb54d..09af01e 100644
--- a/setup/SPOTHRCF.i
+++ b/setup/SPOTHRCF.c
@@ -17,6 +17,8 @@
 	program SPecific write OTHer ConFiguration files
 */
 
+#include "COREDEFS.h"
+
 LOCALPROC WriteAppCNFGGLOBContents(void)
 {
 	WriteCommonCNFGGLOBContents();
diff --git a/setup/USFILDEF.i b/setup/USFILDEF.c
similarity index 99%
rename from setup/USFILDEF.i
rename to setup/USFILDEF.c
index 8d7e7d3..4cdbb7a 100644
--- a/setup/USFILDEF.i
+++ b/setup/USFILDEF.c
@@ -17,6 +17,8 @@
 	USe program SPecific FILe DEFinitions
 */
 
+#include "COREDEFS.h"
+
 LOCALPROC NullProc(void)
 {
 }
diff --git a/setup/WRCNFGAP.i b/setup/WRCNFGAP.c
similarity index 99%
rename from setup/WRCNFGAP.i
rename to setup/WRCNFGAP.c
index 087733b..cd890c0 100644
--- a/setup/WRCNFGAP.i
+++ b/setup/WRCNFGAP.c
@@ -17,6 +17,8 @@
 	WRite "CNFGrAPi.h"
 */
 
+#include "COREDEFS.h"
+
 LOCALPROC WriteOSXLocalTalkCNFGRAPI(void)
 {
 	WriteDestFileLn("#include <unistd.h>");
diff --git a/setup/WRCNFGGL.i b/setup/WRCNFGGL.c
similarity index 99%
rename from setup/WRCNFGGL.i
rename to setup/WRCNFGGL.c
index e49334f..dfaad79 100644
--- a/setup/WRCNFGGL.i
+++ b/setup/WRCNFGGL.c
@@ -17,6 +17,8 @@
 	WRite "CNFGGLob.h"
 */
 
+#include "COREDEFS.h"
+
 
 LOCALPROC WriteConfigurationWarning(void)
 {
diff --git a/setup/WRMACRES.i b/setup/WRMACRES.c
similarity index 99%
rename from setup/WRMACRES.i
rename to setup/WRMACRES.c
index 1848a97..ba8deed 100644
--- a/setup/WRMACRES.i
+++ b/setup/WRMACRES.c
@@ -17,6 +17,8 @@
 	WRite MACintosh RESources configuration
 */
 
+#include "COREDEFS.h"
+
 
 LOCALPROC WriteBeginResResource(char *types, int id)
 {
diff --git a/setup/WRMPLIST.i b/setup/WRMPLIST.c
similarity index 99%
rename from setup/WRMPLIST.i
rename to setup/WRMPLIST.c
index fcfb89b..02707da 100644
--- a/setup/WRMPLIST.i
+++ b/setup/WRMPLIST.c
@@ -17,6 +17,7 @@
 	WRite Macintosh PLIST
 */
 
+#include "COREDEFS.h"
 
 enum {
 	kPListRaw, /* native plist data */
diff --git a/setup/WRTEXTFL.i b/setup/WRTEXTFL.c
similarity index 99%
rename from setup/WRTEXTFL.i
rename to setup/WRTEXTFL.c
index f679765..347a33c 100644
--- a/setup/WRTEXTFL.i
+++ b/setup/WRTEXTFL.c
@@ -17,6 +17,7 @@
 	WRite TEXT FiLe
 */
 
+#include "COREDEFS.h"
 
 
 /* --- routines for writing text files --- */
diff --git a/setup/config.h b/setup/config.h
new file mode 100644
index 0000000..61cd872
--- /dev/null
+++ b/setup/config.h
@@ -0,0 +1,8 @@
+/*
+	Configuration file
+
+	Insert overrides for defaults.h and options.h here
+*/
+
+#include "config/defaults.h"
+#include "config/options.h"
diff --git a/setup/CNFGDLFT.i b/setup/config/defaults.h
similarity index 77%
rename from setup/CNFGDLFT.i
rename to setup/config/defaults.h
index df36eb9..5ca082a 100644
--- a/setup/CNFGDLFT.i
+++ b/setup/config/defaults.h
@@ -1,5 +1,5 @@
 /*
-	CNFGDLFT.i
+	defaults.h
 	Copyright (C) 2018 Paul C. Pratt
 
 	You can redistribute this file and/or modify it under the terms
@@ -16,7 +16,7 @@
 /*
 	CoNFiGuration DeFauLTs
 
-	set default values for things not set in CONFIGUR.i
+	set default values for things not set in config.h
 */
 
 
@@ -32,6 +32,8 @@
 
 #ifndef cur_ide
 
+/* Automatic IDE selection */
+/* TODO: Fill out and/or remove other compilers */
 #ifdef applec
 #define cur_ide gbk_ide_mpw
 #else
@@ -40,7 +42,8 @@
 
 #endif /* cur_ide */
 
-
+/* Determine the IDE version, if applicable */
+/* TODO: Fill out and/or remove other compilers */
 #ifndef ide_vers
 
 #if gbk_ide_xcd == cur_ide
@@ -53,12 +56,14 @@
 
 #endif /* ide_vers */
 
-
+/* Use command line for ??? */
 #ifndef UseCmndLine
 #define UseCmndLine 0
 #endif
 
 
+/* Check if we're on classic Mac OS, which can only store executables in */
+/* 32-kilobyte segments */
 #ifndef NeedSegmenting
 
 #if gbk_ide_mpw == cur_ide
@@ -70,6 +75,7 @@
 #endif /* NeedSegmenting */
 
 
+/* Automatically determine makefile output format */
 #ifndef gbo_script
 
 #if gbk_ide_mpw == cur_ide
diff --git a/setup/CNFGOPTS.i b/setup/config/options.h
similarity index 95%
rename from setup/CNFGOPTS.i
rename to setup/config/options.h
index 1cba01c..2395195 100644
--- a/setup/CNFGOPTS.i
+++ b/setup/config/options.h
@@ -1,5 +1,5 @@
 /*
-	CNFGOPTS.i
+	options.h
 	Copyright (C) 2018 Paul C. Pratt
 
 	You can redistribute this file and/or modify it under the terms
@@ -14,14 +14,13 @@
 */
 
 /*
-	CoNFiGuration OPTionS
+	Configuration Options
 
-	choices that can be used in CONFIGUR.i
+	choices that can be used in config.h
 */
 
 
 /* choices for cur_ide */
-
 #define gbk_ide_mpw 1 /* Macintosh Programmers Workshop */
 #define gbk_ide_mw8 2 /* Metrowerks CodeWarrior */
 #define gbk_ide_bgc 3 /* Gnu tools */
@@ -40,7 +39,6 @@
 #define gbk_ide_mvc 15 /* Mini vMac C (a specific version of gcc) */
 
 /* choices for gbo_script */
-
 #define gbk_script_mpw 1
 #define gbk_script_applescript 2
 #define gbk_script_bash 3
diff --git a/setup/WRDVCFLS.i b/setup/makefiles/bloodshed.c
similarity index 100%
rename from setup/WRDVCFLS.i
rename to setup/makefiles/bloodshed.c
diff --git a/setup/WRDMCFLS.i b/setup/makefiles/digitalmars.c
similarity index 100%
rename from setup/WRDMCFLS.i
rename to setup/makefiles/digitalmars.c
diff --git a/setup/WRBGCFLS.i b/setup/makefiles/gcc.c
similarity index 99%
rename from setup/WRBGCFLS.i
rename to setup/makefiles/gcc.c
index 507ba52..c0b38c3 100644
--- a/setup/WRBGCFLS.i
+++ b/setup/makefiles/gcc.c
@@ -17,6 +17,8 @@
 	WRite Bash Gnu C specific FiLeS
 */
 
+#include "../COREDEFS.h"
+#include "../config.h"
 
 #define WriteXCDcallgcc WriteCompileCExec
 #if 0
diff --git a/setup/makefiles/gcc.h b/setup/makefiles/gcc.h
new file mode 100644
index 0000000..6869a04
--- /dev/null
+++ b/setup/makefiles/gcc.h
@@ -0,0 +1,9 @@
+#ifndef _GCC_H
+#include _GCC_H
+
+#include "../COREDEFS.h"
+
+LOCALPROC WriteBashGccSpecificFiles(void);
+#define WriteSpecificFiles WriteBashGccSpecificFiles
+
+#endif
\ No newline at end of file
diff --git a/setup/WRCCCFLS.i b/setup/makefiles/generic.c
similarity index 100%
rename from setup/WRCCCFLS.i
rename to setup/makefiles/generic.c
diff --git a/setup/WRLCCFLS.i b/setup/makefiles/lcc.c
similarity index 100%
rename from setup/WRLCCFLS.i
rename to setup/makefiles/lcc.c
diff --git a/setup/makefiles/makefiles.h b/setup/makefiles/makefiles.h
new file mode 100644
index 0000000..aeaf99d
--- /dev/null
+++ b/setup/makefiles/makefiles.h
@@ -0,0 +1,61 @@
+#ifndef _MAKEFILES_H
+#define _MAKEFILES_H
+
+#include "../config.h"
+
+/* Include the corresponsing platform-specific file */
+
+#if gbk_ide_mpw == cur_ide
+#include "mpw.h"
+#endif
+
+#if gbk_ide_mw8 == cur_ide
+#include "metrowerks8.h"
+#endif
+
+#if gbk_ide_mvc == cur_ide
+#include "minivmac.h"
+#endif
+
+#if (gbk_ide_bgc == cur_ide) \
+	|| (gbk_ide_cyg == cur_ide) \
+	|| (gbk_ide_mgw == cur_ide) \
+	|| (gbk_ide_dkp == cur_ide) \
+	|| (gbk_ide_dvc == cur_ide) \
+	|| (gbk_ide_xcd == cur_ide)
+#include "gcc.h"
+#endif
+
+#if gbk_ide_snc == cur_ide
+#include "sun.h"
+#endif
+
+#if gbk_ide_msv == cur_ide
+#include "msvc.h"
+#endif
+
+#if gbk_ide_lcc == cur_ide
+#include "lcc.h"
+#endif
+
+#if gbk_ide_dvc == cur_ide
+#include "bloodshed.h"
+#endif
+
+#if gbk_ide_xcd == cur_ide
+#include "xcode.h"
+#endif
+
+#if gbk_ide_dmc == cur_ide
+#include "digitalmars.h"
+#endif
+
+#if gbk_ide_plc == cur_ide
+#include "pelles.h"
+#endif
+
+#if gbk_ide_ccc == cur_ide
+#include "generic.h"
+#endif
+
+#endif
diff --git a/setup/WRMW8FLS.i b/setup/makefiles/metrowerks8.c
similarity index 100%
rename from setup/WRMW8FLS.i
rename to setup/makefiles/metrowerks8.c
diff --git a/setup/WRMVCFLS.i b/setup/makefiles/minivmac.c
similarity index 100%
rename from setup/WRMVCFLS.i
rename to setup/makefiles/minivmac.c
diff --git a/setup/WRMPWFLS.i b/setup/makefiles/mpw.c
similarity index 100%
rename from setup/WRMPWFLS.i
rename to setup/makefiles/mpw.c
diff --git a/setup/WRMSCFLS.i b/setup/makefiles/msvc.c
similarity index 100%
rename from setup/WRMSCFLS.i
rename to setup/makefiles/msvc.c
diff --git a/setup/WRPLCFLS.i b/setup/makefiles/pelles.c
similarity index 100%
rename from setup/WRPLCFLS.i
rename to setup/makefiles/pelles.c
diff --git a/setup/WRSNCFLS.i b/setup/makefiles/sun.c
similarity index 100%
rename from setup/WRSNCFLS.i
rename to setup/makefiles/sun.c
diff --git a/setup/WRXCDFLS.i b/setup/makefiles/xcode.c
similarity index 100%
rename from setup/WRXCDFLS.i
rename to setup/makefiles/xcode.c
diff --git a/setup/tool.c b/setup/tool.c
index 7ea297d..8657148 100644
--- a/setup/tool.c
+++ b/setup/tool.c
@@ -17,11 +17,8 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "COREDEFS.i"
-
-#include "CNFGOPTS.i"
-#include "CONFIGUR.i"
-#include "CNFGDLFT.i"
+#include "COREDEFS.h"
+#include "config.h"
 
 
 #define MyMoveBytes(src, dst, n) \
@@ -78,58 +75,7 @@
 #pragma segment Body3
 #endif
 
-#if gbk_ide_mpw == cur_ide
-#include "WRMPWFLS.i"
-#endif
-
-#if gbk_ide_mw8 == cur_ide
-#include "WRMW8FLS.i"
-#endif
-
-#if gbk_ide_mvc == cur_ide
-#include "WRMVCFLS.i"
-#endif
-
-#if (gbk_ide_bgc == cur_ide) \
-	|| (gbk_ide_cyg == cur_ide) \
-	|| (gbk_ide_mgw == cur_ide) \
-	|| (gbk_ide_dkp == cur_ide) \
-	|| (gbk_ide_dvc == cur_ide) \
-	|| (gbk_ide_xcd == cur_ide)
-#include "WRBGCFLS.i"
-#endif
-
-#if gbk_ide_snc == cur_ide
-#include "WRSNCFLS.i"
-#endif
-
-#if gbk_ide_msv == cur_ide
-#include "WRMSCFLS.i"
-#endif
-
-#if gbk_ide_lcc == cur_ide
-#include "WRLCCFLS.i"
-#endif
-
-#if gbk_ide_dvc == cur_ide
-#include "WRDVCFLS.i"
-#endif
-
-#if gbk_ide_xcd == cur_ide
-#include "WRXCDFLS.i"
-#endif
-
-#if gbk_ide_dmc == cur_ide
-#include "WRDMCFLS.i"
-#endif
-
-#if gbk_ide_plc == cur_ide
-#include "WRPLCFLS.i"
-#endif
-
-#if gbk_ide_ccc == cur_ide
-#include "WRCCCFLS.i"
-#endif
+#include "makefiles/makefiles.h"
 
 #if NeedSegmenting
 #pragma segment Body4
diff --git a/setup/CMDARGT1.i b/setup/utilities/CMDARGT1.c
similarity index 98%
rename from setup/CMDARGT1.i
rename to setup/utilities/CMDARGT1.c
index c165a72..b1c252f 100644
--- a/setup/CMDARGT1.i
+++ b/setup/utilities/CMDARGT1.c
@@ -20,6 +20,7 @@
 	used to make an MPW tool.
 */
 
+#include "COREDEFS.h"
 
 LOCALVAR int The_argc;
 LOCALVAR int The_argi;
diff --git a/setup/STRUTILS.i b/setup/utilities/STRUTILS.c
similarity index 99%
rename from setup/STRUTILS.i
rename to setup/utilities/STRUTILS.c
index 4f92519..09079fc 100644
--- a/setup/STRUTILS.i
+++ b/setup/utilities/STRUTILS.c
@@ -19,6 +19,8 @@
 	Some very basic string macros and routines.
 */
 
+#include "COREDEFS.h"
+
 
 #define PStrLength(s) (*(s))
 #define PStrToMyCharPtr(s) ((s) + 1)