diff --git a/commands/CmdCD.c b/commands/CmdCD.c
index ec88a23d..7ba4458d 100644
--- a/commands/CmdCD.c
+++ b/commands/CmdCD.c
@@ -24,6 +24,7 @@ static const char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magi
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
+#include <unistd.h>
 
 #include "tcltk/tclmagic.h"
 #include "utils/magic.h"
diff --git a/lef/defWrite.c b/lef/defWrite.c
index 3d77c4f2..7576dc20 100644
--- a/lef/defWrite.c
+++ b/lef/defWrite.c
@@ -18,6 +18,7 @@ static const char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magi
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <unistd.h>
 
 #include "tcltk/tclmagic.h"
 #include "utils/magic.h"
diff --git a/plot/plotRutils.c b/plot/plotRutils.c
index 8b4b22ee..9e252b72 100644
--- a/plot/plotRutils.c
+++ b/plot/plotRutils.c
@@ -27,6 +27,7 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
+#include <unistd.h>
 
 #include "utils/magic.h"
 #include "utils/geometry.h"
diff --git a/plot/plotVers.c b/plot/plotVers.c
index 447c1611..ea4ed2a2 100644
--- a/plot/plotVers.c
+++ b/plot/plotVers.c
@@ -23,6 +23,7 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
 
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 
 /* C99 compat */
 #include <stdlib.h>
diff --git a/plow/PlowRandom.c b/plow/PlowRandom.c
index 56615658..e62c13b6 100644
--- a/plow/PlowRandom.c
+++ b/plow/PlowRandom.c
@@ -30,6 +30,7 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
 #include <sys/types.h>
 #include <sys/file.h>
 #include <sys/stat.h>
+#include <unistd.h>
 #if defined(SYSV) || defined(EMSCRIPTEN)
 #include <fcntl.h>
 #endif
diff --git a/textio/txMain.c b/textio/txMain.c
index c39bf9ad..17e2b185 100644
--- a/textio/txMain.c
+++ b/textio/txMain.c
@@ -24,6 +24,7 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
 #include <sys/types.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 
 #include "utils/magsgtty.h"
 #include "utils/magic.h"
diff --git a/utils/path.c b/utils/path.c
index accd41d6..3f1bfd62 100644
--- a/utils/path.c
+++ b/utils/path.c
@@ -29,6 +29,7 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <unistd.h>
 
 #ifdef HAVE_ZLIB
 #include <zlib.h>