diff --git a/include/ace.h b/include/ace.h
index fba672227..8ce86e18f 100644
--- a/include/ace.h
+++ b/include/ace.h
@@ -45,9 +45,7 @@
 
 
 
-#ifndef _STDDEF_H
 #include <stddef.h>
-#endif
 
 
 
diff --git a/include/apple2.h b/include/apple2.h
index 31e56a95a..f217ad04c 100644
--- a/include/apple2.h
+++ b/include/apple2.h
@@ -41,9 +41,10 @@
 #  error This module may only be used when compiling for the Apple ][!
 #endif
 
-
 #include <apple2_filetype.h>
 
+
+
 /*****************************************************************************/
 /*                                   Data                                    */
 /*****************************************************************************/
diff --git a/include/apple2enh.h b/include/apple2enh.h
index cc62f70b7..77328b5ed 100644
--- a/include/apple2enh.h
+++ b/include/apple2enh.h
@@ -42,10 +42,7 @@
 
 
 
-/* If not already done, include the apple2.h header file */
-#if !defined(_APPLE2_H)
-#  include <apple2.h>
-#endif
+#include <apple2.h>
 
 
 
diff --git a/include/atari.h b/include/atari.h
index bf1af7d7b..4bed8d7a7 100644
--- a/include/atari.h
+++ b/include/atari.h
@@ -355,5 +355,7 @@ struct __iocb {
 #define IOCB_GETCWD      0x30  /* get current directory (MyDOS/SpartaDOS) */
 #define IOCB_FORMAT      0xFE  /* format */
 
+
+
 /* End of atari.h */
 #endif
diff --git a/include/atari2600.h b/include/atari2600.h
index 1eb51a2dd..a6b5cda47 100644
--- a/include/atari2600.h
+++ b/include/atari2600.h
@@ -8,9 +8,13 @@
 /*                                                                           */
 /*****************************************************************************/
 
+
+
 #ifndef _ATARI2600_H
 #define _ATARI2600_H
 
+
+
 /* Check for errors */
 #if !defined(__ATARI2600__)
 #  error This module may only be used when compiling for the Atari 2600!
@@ -22,5 +26,7 @@
 #include <_riot.h>
 #define RIOT (*(struct __riot*)0x0280)
 
+
+
 /* End of atari2600.h */
-#endif /* #ifndef _ATARI2600_H */
+#endif
diff --git a/include/c16.h b/include/c16.h
index d49ca6fd4..c039218f9 100644
--- a/include/c16.h
+++ b/include/c16.h
@@ -47,9 +47,7 @@
 
 /* Include the base header file for the 264 series. include file.
  */
-#ifndef _CBM264_H
 #include <cbm264.h>
-#endif
 
 
 
diff --git a/include/cbm.h b/include/cbm.h
index da63375b2..1395f700f 100644
--- a/include/cbm.h
+++ b/include/cbm.h
@@ -46,10 +46,7 @@
 
 
 /* We need NULL. */
-
-#if !defined(_STDDEF_H)
-#  include <stddef.h>
-#endif
+#include <stddef.h>
 
 /* Load the system-specific files here, if needed. */
 #if   defined(__C64__)    && !defined(_C64_H)
diff --git a/include/geos.h b/include/geos.h
index ae356d679..3f760b6ad 100644
--- a/include/geos.h
+++ b/include/geos.h
@@ -19,53 +19,19 @@
 
 
 
-#ifndef _GCONST_H
 #include <geos/gconst.h>
-#endif
-
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
-
-#ifndef _GSYM_H
 #include <geos/gsym.h>
-#endif
-
-#ifndef _GDISK_H
 #include <geos/gdisk.h>
-#endif
-
-#ifndef _GFILE_H
 #include <geos/gfile.h>
-#endif
-
-#ifndef _GPROCESS_H
 #include <geos/gprocess.h>
-#endif
-
-#ifndef _GGRAPH_H
 #include <geos/ggraph.h>
-#endif
-
-#ifndef _GMENU_H
 #include <geos/gmenu.h>
-#endif
-
-#ifndef _GSPRITE_H
 #include <geos/gsprite.h>
-#endif
-
-#ifndef _GMEMORY_H
 #include <geos/gmemory.h>
-#endif
-
-#ifndef _GSYS_H
 #include <geos/gsys.h>
-#endif
-
-#ifndef _GDLGBOX_H
 #include <geos/gdlgbox.h>
-#endif
+
 
 
 #define CH_ULCORNER             '+'
@@ -140,5 +106,6 @@
 #define JOY_BTN_1_MASK          0x10
 
 
+
 /* End of geos.h */
 #endif
diff --git a/include/geos/gdisk.h b/include/geos/gdisk.h
index f65d7d301..30305a2fc 100644
--- a/include/geos/gdisk.h
+++ b/include/geos/gdisk.h
@@ -7,9 +7,7 @@
 #ifndef _GDISK_H
 #define _GDISK_H
 
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
 
 char __fastcall__ ReadBuff(struct tr_se *myTrSe);
 char __fastcall__ WriteBuff(struct tr_se *myTrSe);
diff --git a/include/geos/gfile.h b/include/geos/gfile.h
index d7667d8ec..ec7a75bbc 100644
--- a/include/geos/gfile.h
+++ b/include/geos/gfile.h
@@ -7,9 +7,7 @@
 #ifndef _GFILE_H
 #define _GFILE_H
 
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
 
 struct filehandle *Get1stDirEntry(void);
 struct filehandle *GetNxtDirEntry(void);
diff --git a/include/geos/ggraph.h b/include/geos/ggraph.h
index 961ec2d80..35e02c198 100644
--- a/include/geos/ggraph.h
+++ b/include/geos/ggraph.h
@@ -7,9 +7,7 @@
 #ifndef _GGRAPH_H
 #define _GGRAPH_H
 
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
 
 void __fastcall__ SetPattern(char newpattern);
 
diff --git a/include/geos/gmemory.h b/include/geos/gmemory.h
index 3fba5cb5b..ba8e9f211 100644
--- a/include/geos/gmemory.h
+++ b/include/geos/gmemory.h
@@ -7,9 +7,7 @@
 #ifndef _GMEMORY_H
 #define _GMEMORY_H
 
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
 
 void __fastcall__ CopyString(char *dest, const char *source);
 char __fastcall__ CmpString(const char *dest, const char *source);
diff --git a/include/geos/gmenu.h b/include/geos/gmenu.h
index 3175b6cf3..89caa2c02 100644
--- a/include/geos/gmenu.h
+++ b/include/geos/gmenu.h
@@ -7,9 +7,7 @@
 #ifndef _GMENU_H
 #define _GMENU_H
 
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
 
 void __fastcall__ DoMenu(struct menu *myMenu);
 void ReDoMenu(void);
diff --git a/include/geos/gprocess.h b/include/geos/gprocess.h
index 6fab2ecfa..000003f32 100644
--- a/include/geos/gprocess.h
+++ b/include/geos/gprocess.h
@@ -7,9 +7,7 @@
 #ifndef _GPROCESS_H
 #define _GPROCESS_H
 
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
 
 void __fastcall__ InitProcesses(char number, struct process *proctab);
 void __fastcall__ RestartProcess(char number);
diff --git a/include/geos/gsym.h b/include/geos/gsym.h
index 085046674..2b2c8fbb2 100644
--- a/include/geos/gsym.h
+++ b/include/geos/gsym.h
@@ -7,9 +7,7 @@
 #ifndef _GSYM_H
 #define _GSYM_H
 
-#ifndef _GSTRUCT_H
 #include <geos/gstruct.h>
-#endif
 
 #define r0              (*(unsigned*)(R_BASE + 0x00))
 #define r0L             (*(char*)(R_BASE + 0x00))
diff --git a/include/lynx.h b/include/lynx.h
index 3629f322e..4b0390a13 100644
--- a/include/lynx.h
+++ b/include/lynx.h
@@ -123,6 +123,8 @@ extern void lynx_160_102_16_tgi[];    /* Referred to by tgi_static_stddrv[] */
 /*                           Sound support                                   */
 /*****************************************************************************/
 
+
+
 void lynx_snd_init (void);
 /* Initialize the sound driver */
 
@@ -144,6 +146,8 @@ void __fastcall__ lynx_snd_stop_channel (unsigned char channel);
 unsigned char lynx_snd_active(void);
 /* Show which channels are active */
 
+
+
 /*****************************************************************************/
 /*                           Accessing the cart                              */
 /*****************************************************************************/
@@ -209,5 +213,6 @@ unsigned __fastcall__ lynx_eewrite (unsigned cell, unsigned val);
 #define SUZY        (*(struct __suzy*)0xFC00)
 
 
+
 /* End of lynx.h */
 #endif
diff --git a/include/plus4.h b/include/plus4.h
index 840e8b342..81e3c5286 100644
--- a/include/plus4.h
+++ b/include/plus4.h
@@ -47,9 +47,7 @@
 
 /* Include the base header file for the 264 series. include file.
  */
-#ifndef _CBM264_H
 #include <cbm264.h>
-#endif
 
 /* Define hardware */
 #include <_6551.h>
diff --git a/include/stdio.h b/include/stdio.h
index a3facd513..73dc05bdb 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -38,12 +38,8 @@
 
 
 
-#ifndef _STDDEF_H
-#  include <stddef.h>
-#endif
-#ifndef _STDARG_H
-#  include <stdarg.h>
-#endif
+#include <stddef.h>
+#include <stdarg.h>
 
 
 
@@ -147,6 +143,3 @@ void __fastcall__ _poserror (const char* msg);          /* cc65 */
 
 /* End of stdio.h */
 #endif
-
-
-