diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1229d30..d9810a9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -59,22 +59,9 @@ IF(CMAKE_SYSTEM_PROCESSOR MATCHES "arm.*" OR
   )
 ENDIF()
 
-IF(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
-  LIST(APPEND MAIKO_DEFINITIONS
-    "-DMACOSX"
-  )
-ELSEIF(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
-  LIST(APPEND MAIKO_DEFINITIONS
-    "-DFREEBSD"
-  )
-ELSEIF(CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
-  LIST(APPEND MAIKO_DEFINITIONS
-    "-DOPENBSD"
-  )
-ELSEIF(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+IF(CMAKE_SYSTEM_NAME STREQUAL "Linux")
   LIST(APPEND MAIKO_DEFINITIONS
     "-DAIX" # This is temporary
-    "-DLINUX"
   )
 ELSEIF(CMAKE_SYSTEM_NAME STREQUAL "SunOS")
   LIST(APPEND MAIKO_DEFINITIONS
diff --git a/bin/makefile-darwin.386-x b/bin/makefile-darwin.386-x
index 7700ff4..1749c7a 100644
--- a/bin/makefile-darwin.386-x
+++ b/bin/makefile-darwin.386-x
@@ -21,7 +21,7 @@ OPTFLAGS =  -O2 -g
 DISPOPTFLAGS = -O2 -g
 FPFLAGS =
 DEBUGFLAGS = # -DDEBUG -DOPTRACE
-DFLAGS = $(DEBUGFLAGS) -DMACOSX -DOLD_CURSOR \
+DFLAGS = $(DEBUGFLAGS) -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351 -DSTACKCHECK -DFSBCHECK -DPCTRACE
 
diff --git a/bin/makefile-darwin.aarch64-x b/bin/makefile-darwin.aarch64-x
index 7fe4690..e10fbdf 100644
--- a/bin/makefile-darwin.aarch64-x
+++ b/bin/makefile-darwin.aarch64-x
@@ -21,7 +21,7 @@ OPTFLAGS =  -O1 -g
 DISPOPTFLAGS = -O1 -g
 FPFLAGS =
 DEBUGFLAGS = # -DDEBUG -DOPTRACE
-DFLAGS = $(DEBUGFLAGS) -DMACOSX -DOLD_CURSOR \
+DFLAGS = $(DEBUGFLAGS) -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351
 
diff --git a/bin/makefile-darwin.x86_64-x b/bin/makefile-darwin.x86_64-x
index bc7cb9d..48638ab 100644
--- a/bin/makefile-darwin.x86_64-x
+++ b/bin/makefile-darwin.x86_64-x
@@ -21,7 +21,7 @@ OPTFLAGS =  -O1 -g
 DISPOPTFLAGS = -O1 -g
 FPFLAGS =
 DEBUGFLAGS = # -DDEBUG -DOPTRACE
-DFLAGS = $(DEBUGFLAGS) -DMACOSX -DOLD_CURSOR \
+DFLAGS = $(DEBUGFLAGS) -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351
 
diff --git a/bin/makefile-freebsd.386-x b/bin/makefile-freebsd.386-x
index 4ea86a3..8355993 100644
--- a/bin/makefile-freebsd.386-x
+++ b/bin/makefile-freebsd.386-x
@@ -21,7 +21,7 @@ OEXT = .o
 OPTFLAGS = -O1 -gdwarf-2
 DISPOPTFLAGS = -O1 -gdwarf-2 
 FPFLAGS =
-DFLAGS = -DFREEBSD -DOLD_CURSOR \
+DFLAGS = -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351
 
diff --git a/bin/makefile-init.386 b/bin/makefile-init.386
index e60c55a..15e44f2 100644
--- a/bin/makefile-init.386
+++ b/bin/makefile-init.386
@@ -20,7 +20,7 @@ XFLAGS = -I/opt/X11/include -DXWINDOW -DNOPIXRECT
 OPTFLAGS =  -O0 -g
 DISPOPTFLAGS = -O0 -g
 FPFLAGS =
-DFLAGS = -DMACOSX -DOLD_CURSOR \
+DFLAGS = -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351 -DNOVERSION -DINIT -DTRACE -DOPTRACE
 
diff --git a/bin/makefile-linux.386-x b/bin/makefile-linux.386-x
index faec22c..5091bbb 100644
--- a/bin/makefile-linux.386-x
+++ b/bin/makefile-linux.386-x
@@ -21,7 +21,7 @@ OEXT = .o
 OPTFLAGS =  -O2 -g3
 DISPOPTFLAGS = -O2 -g3
 FPFLAGS =
-DFLAGS = -DLINUX -DAIX -DOLD_CURSOR \
+DFLAGS = -DAIX -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351
 
diff --git a/bin/makefile-linux.armv7l-x b/bin/makefile-linux.armv7l-x
index 352d973..0d5b201 100644
--- a/bin/makefile-linux.armv7l-x
+++ b/bin/makefile-linux.armv7l-x
@@ -21,7 +21,7 @@ OEXT = .o
 OPTFLAGS =  -O2 -g3
 DISPOPTFLAGS = -O2 -g3
 FPFLAGS =
-DFLAGS = -DLINUX -DAIX -DOLD_CURSOR \
+DFLAGS = -DAIX -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351
 
diff --git a/bin/makefile-linux.x86_64-x b/bin/makefile-linux.x86_64-x
index 683657e..72429db 100644
--- a/bin/makefile-linux.x86_64-x
+++ b/bin/makefile-linux.x86_64-x
@@ -22,7 +22,7 @@ OEXT = .o
 OPTFLAGS =  -O2 -g3
 DISPOPTFLAGS = -O2 -g3
 FPFLAGS =
-DFLAGS = -DLINUX -DAIX -DOLD_CURSOR \
+DFLAGS = -DAIX -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351
 
diff --git a/bin/makefile-openbsd.x86_64-x b/bin/makefile-openbsd.x86_64-x
index 6125b1d..6e419a6 100644
--- a/bin/makefile-openbsd.x86_64-x
+++ b/bin/makefile-openbsd.x86_64-x
@@ -21,7 +21,7 @@ OEXT = .o
 OPTFLAGS =  -O2 -g3
 DISPOPTFLAGS = -O2 -g3
 FPFLAGS =
-DFLAGS = -DOPENBSD -DAIX -DOLD_CURSOR \
+DFLAGS = -DAIX -DOLD_CURSOR \
 	-DBYTESWAP -DLOGINT  $(XFLAGS) \
 	-DRELEASE=351
 
diff --git a/src/timer.c b/src/timer.c
index 34251af..d8a952b 100644
--- a/src/timer.c
+++ b/src/timer.c
@@ -250,7 +250,7 @@ static int gettime(int casep)
       /* Unfortunately, FreeBSD does not support the timezone external variable, nor   */
       /* does gettimeofday() seem to produce the correct timezone values.	       */
       tzset();
-#if defined(FREEBSD)
+#if defined(MAIKO_OS_FREEBSD)
       time_t tv = time(NULL);
       struct tm *tm = localtime(&tv);
       return (tm->tm_gmtoff / -3600);
diff --git a/src/uraid.c b/src/uraid.c
index 10cae29..7eda37b 100644
--- a/src/uraid.c
+++ b/src/uraid.c
@@ -54,7 +54,7 @@ extern int Win_security_p;
 #include <stropts.h>
 #endif /* OS5 */
 
-#if defined(FREEBSD) || defined(MACOSX) || defined(OS5)
+#if defined(MAIKO_OS_FREEBSD) || defined(MAIKO_OS_MACOS) || defined(OS5)
 /* vfork is deprecated */
 #define vfork fork
 #endif
diff --git a/src/uutils.c b/src/uutils.c
index 80d4174..693b115 100644
--- a/src/uutils.c
+++ b/src/uutils.c
@@ -227,7 +227,7 @@ LispPTR unix_getparm(LispPTR *args) {
     envvalue = "i386";
 #elif defined(DOS)
     envvalue = "386";
-#elif defined(MACOSX)
+#elif defined(MAIKO_OS_MACOS)
     envvalue = "i386";
 #else
     envvalue = "mc68020";
@@ -240,7 +240,7 @@ LispPTR unix_getparm(LispPTR *args) {
     envvalue = "sun386";
 #elif defined(DOS)
     envvalue = "dos";
-#elif defined(MACOSX)
+#elif defined(MAIKO_OS_MACOS)
     envvalue = "i386";
 #else
     envvalue = "sun3";