diff --git a/lib/mksh/dosys.cc b/lib/mksh/dosys.cc
index 68c9ca2..e8be6c4 100644
--- a/lib/mksh/dosys.cc
+++ b/lib/mksh/dosys.cc
@@ -51,15 +51,16 @@
 #include <sys/wait.h>		/* wait() */
 #include <ulimit.h>		/* ulimit() */
 #include <unistd.h>		/* close(), dup2() */
-// closefrom only available on Solaris/BSD
+// closefrom only available on Solaris/BSD via system header
 #include <stdlib.h>		/* closefrom() */
-#ifdef __linux
-  #include <bsd/unistd.h>
-#endif
 #include <libintl.h>
 
 #include <config.h>
 
+#if defined(__linux) && defined(HAVE_CLOSEFROM)
+  #include <bsd/unistd.h>
+#endif
+
 /*
  * typedefs & structs
  */