diff --git a/src/d_main.c b/src/d_main.c
index 23a2c0133..cc02c5398 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -15,7 +15,7 @@
 ///        plus functions to parse command line parameters, configure game
 ///        parameters, and call the startup functions.
 
-#if (defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)
+#if defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)
 #include <sys/stat.h>
 #include <sys/types.h>
 #endif
@@ -934,7 +934,7 @@ static void IdentifyVersion(void)
 	char *srb2wad;
 	const char *srb2waddir = NULL;
 
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+#if defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)
 	// change to the directory where 'srb2.pk3' is found
 	srb2waddir = I_LocateWad();
 #endif
@@ -1107,7 +1107,7 @@ void D_SRB2Main(void)
 
 		if (!userhome)
 		{
-#if ((defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)) && !defined (__CYGWIN__)
+#if (defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)) && !defined (__CYGWIN__)
 			I_Error("Please set $HOME to your home directory\n");
 #else
 			if (dedicated)
@@ -1287,7 +1287,7 @@ void D_SRB2Main(void)
 
 	G_LoadGameData();
 
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+#if defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)
 	VID_PrepareModeList(); // Regenerate Modelist according to cv_fullscreen
 #endif
 
@@ -1553,7 +1553,7 @@ const char *D_Home(void)
 		userhome = M_GetNextParm();
 	else
 	{
-#if !((defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)) && !defined (__APPLE__)
+#if !(defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON))
 		if (FIL_FileOK(CONFIGFILENAME))
 			usehome = false; // Let's NOT use home
 		else
diff --git a/src/d_netcmd.c b/src/d_netcmd.c
index 09f9d4651..e2ccd0172 100644
--- a/src/d_netcmd.c
+++ b/src/d_netcmd.c
@@ -168,7 +168,7 @@ void SendWeaponPref(void);
 void SendWeaponPref2(void);
 
 static CV_PossibleValue_t usemouse_cons_t[] = {{0, "Off"}, {1, "On"}, {2, "Force"}, {0, NULL}};
-#if (defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)
+#if defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)
 static CV_PossibleValue_t mouse2port_cons_t[] = {{0, "/dev/gpmdata"}, {1, "/dev/ttyS0"},
 	{2, "/dev/ttyS1"}, {3, "/dev/ttyS2"}, {4, "/dev/ttyS3"}, {0, NULL}};
 #else
@@ -255,7 +255,7 @@ consvar_t cv_joyscale2 = CVAR_INIT ("padscale2", "1", CV_SAVE|CV_CALL, NULL, I_J
 consvar_t cv_joyscale = CVAR_INIT ("padscale", "1", CV_SAVE|CV_HIDEN, NULL, NULL); //Alam: Dummy for save
 consvar_t cv_joyscale2 = CVAR_INIT ("padscale2", "1", CV_SAVE|CV_HIDEN, NULL, NULL); //Alam: Dummy for save
 #endif
-#if (defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)
+#if defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)
 consvar_t cv_mouse2port = CVAR_INIT ("mouse2port", "/dev/gpmdata", CV_SAVE, mouse2port_cons_t, NULL);
 consvar_t cv_mouse2opt = CVAR_INIT ("mouse2opt", "0", CV_SAVE, NULL, NULL);
 #else
@@ -788,7 +788,7 @@ void D_RegisterClientCommands(void)
 	// WARNING: the order is important when initialising mouse2
 	// we need the mouse2port
 	CV_RegisterVar(&cv_mouse2port);
-#if (defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)
+#if defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)
 	CV_RegisterVar(&cv_mouse2opt);
 #endif
 	CV_RegisterVar(&cv_controlperkey);
diff --git a/src/d_netcmd.h b/src/d_netcmd.h
index ac39626a4..59c231255 100644
--- a/src/d_netcmd.h
+++ b/src/d_netcmd.h
@@ -45,7 +45,7 @@ extern consvar_t cv_joyscale2;
 // splitscreen with second mouse
 extern consvar_t cv_mouse2port;
 extern consvar_t cv_usemouse2;
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON)
+#if defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)
 extern consvar_t cv_mouse2opt;
 #endif
 
diff --git a/src/doomdef.h b/src/doomdef.h
index 5f36f2d69..0c88d1add 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -112,7 +112,7 @@
 //#define PARANOIA // do some tests that never fail but maybe
 // turn this on by make etc.. DEBUGMODE = 1 or use the Debug profile in the VC++ projects
 //#endif
-#if defined (_WIN32) || (defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON) || defined (macintosh)
+#if defined (_WIN32) || defined (__unix__) || defined(__APPLE__) || defined (UNIXCOMMON) || defined (macintosh)
 #define LOGMESSAGES // write message in log.txt
 #endif
 
@@ -415,7 +415,7 @@ enum {
 };
 
 // Name of local directory for config files and savegames
-#if (((defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON)) && !defined (__CYGWIN__)) && !defined (__APPLE__)
+#if (defined (__unix__) || defined (UNIXCOMMON)) && !defined (__CYGWIN__) && !defined (__APPLE__)
 #define DEFAULTDIR ".srb2"
 #else
 #define DEFAULTDIR "srb2"
diff --git a/src/doomtype.h b/src/doomtype.h
index ffaa540b1..f04314f54 100644
--- a/src/doomtype.h
+++ b/src/doomtype.h
@@ -97,7 +97,7 @@ typedef long ssize_t;
 	#define strncasecmp             strnicmp
 	#define strcasecmp              strcmpi
 #endif
-#if (defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)
+#if defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)
 	#undef stricmp
 	#define stricmp(x,y) strcasecmp(x,y)
 	#undef strnicmp
diff --git a/src/i_tcp.c b/src/i_tcp.c
index a9f617dc9..f54dd6878 100644
--- a/src/i_tcp.c
+++ b/src/i_tcp.c
@@ -64,7 +64,7 @@
 		#include <errno.h>
 		#include <time.h>
 
-		#if (defined (__unix__) && !defined (MSDOS)) || defined(__APPLE__) || defined (UNIXCOMMON)
+		#if defined (__unix__) || defined (__APPLE__) || defined (UNIXCOMMON)
 			#include <sys/time.h>
 		#endif // UNIXCOMMON
 	#endif
@@ -155,7 +155,7 @@
 	typedef SOCKET SOCKET_TYPE;
 	#define ERRSOCKET (SOCKET_ERROR)
 #else
-	#if (defined (__unix__) && !defined (MSDOS)) || defined (__APPLE__) || defined (__HAIKU__)
+	#if defined (__unix__) || defined (__APPLE__) || defined (__HAIKU__)
 		typedef int SOCKET_TYPE;
 	#else
 		typedef unsigned long SOCKET_TYPE;
diff --git a/src/m_menu.c b/src/m_menu.c
index 516bd34c1..a41c2db26 100644
--- a/src/m_menu.c
+++ b/src/m_menu.c
@@ -1322,7 +1322,7 @@ static menuitem_t OP_Camera2ExtendedOptionsMenu[] =
 enum
 {
 	op_video_resolution = 1,
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+#if defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)
 	op_video_fullscreen,
 #endif
 	op_video_vsync,
@@ -1334,7 +1334,7 @@ static menuitem_t OP_VideoOptionsMenu[] =
 	{IT_HEADER, NULL, "Screen", NULL, 0},
 	{IT_STRING | IT_CALL,  NULL, "Set Resolution...",       M_VideoModeMenu,          6},
 
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+#if defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)
 	{IT_STRING|IT_CVAR,      NULL, "Fullscreen",             &cv_fullscreen,         11},
 #endif
 	{IT_STRING | IT_CVAR, NULL, "Vertical Sync",                &cv_vidwait,         16},
@@ -1453,7 +1453,7 @@ static menuitem_t OP_OpenGLOptionsMenu[] =
 #ifdef ALAM_LIGHTING
 	{IT_SUBMENU|IT_STRING,      NULL, "Lighting...",         &OP_OpenGLLightingDef,   144},
 #endif
-#if defined (_WINDOWS) && (!((defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)))
+#if defined (_WINDOWS) && (!(defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)))
 	{IT_STRING|IT_CVAR,         NULL, "Fullscreen",          &cv_fullscreen,          154},
 #endif
 };
@@ -12923,7 +12923,7 @@ static void M_VideoModeMenu(INT32 choice)
 
 	memset(modedescs, 0, sizeof(modedescs));
 
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+#if defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)
 	VID_PrepareModeList(); // FIXME: hack
 #endif
 	vidm_nummodes = 0;
diff --git a/src/sdl/i_system.c b/src/sdl/i_system.c
index a0dd6e1da..e3a0c2563 100644
--- a/src/sdl/i_system.c
+++ b/src/sdl/i_system.c
@@ -102,7 +102,7 @@ typedef LPVOID (WINAPI *p_MapViewOfFile) (HANDLE, DWORD, DWORD, DWORD, SIZE_T);
 #endif
 #endif
 
-#if (defined (__unix__) && !defined (_MSDOS)) || (defined (UNIXCOMMON) && !defined(__APPLE__))
+#if defined (__unix__) || (defined (UNIXCOMMON) && !defined (__APPLE__))
 #include <errno.h>
 #include <sys/wait.h>
 #define NEWSIGNALHANDLER
diff --git a/src/v_video.c b/src/v_video.c
index 4713db0d8..1c383a2ac 100644
--- a/src/v_video.c
+++ b/src/v_video.c
@@ -418,7 +418,7 @@ void V_SetPalette(INT32 palettenum)
 #ifdef HWRENDER
 	if (rendermode == render_opengl)
 		HWR_SetPalette(&pLocalPalette[palettenum*256]);
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+#if defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)
 	else
 #endif
 #endif
@@ -432,7 +432,7 @@ void V_SetPaletteLump(const char *pal)
 #ifdef HWRENDER
 	if (rendermode == render_opengl)
 		HWR_SetPalette(pLocalPalette);
-#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+#if defined (__unix__) || defined (UNIXCOMMON) || defined (HAVE_SDL)
 	else
 #endif
 #endif