src: remove <unistd.h> from node_os.cc

The file does not use sysconf() and its use of gethostname() has been
removed, so including <unistd.h> appears to be unnecessary.

PR-URL: nodejs/node#44668
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Richard Lau <[email protected]>
Reviewed-By: Jiawen Geng <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: tniessen

src/node_os.cc

@@ -28,7 +28,6 @@
 #endif  // __MINGW32__
 
 #ifdef __POSIX__
-# include <unistd.h>        // gethostname, sysconf
 # include <climits>         // PATH_MAX on Solaris.
 #endif  // __POSIX__