include <unistd.h> where necessary in files using API calls

When global <sys/mman.h> was removed from tile.h it also removed
<unistd.h> nearby.  This exposes the lack of <unistd.h> being
included where needed using APIs like close()/read()/unlink()/isatty()
the WASM build seems to show this as the header file set is structured
differently.

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"

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"

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"

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>

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

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"

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>