--- a/src/code/exports.lisp
+++ b/src/code/exports.lisp
@@ -284,7 +284,9 @@
 	   "FD-CLR"
 
 	   ;; Simple streams
+	   "PROT_READ"
 	   "UNIX-MMAP"
+	   "UNIX-MUNMAP"
 	   "UNIX-MSYNC"
 
 	   ;; Motif
@@ -313,10 +315,6 @@
 	   ;; run-program.lisp
 	   "SGTTYB"
 
-	   ;; Simple streams
-	   "PROT_READ"
-	   "UNIX-MUNMAP"
-
 	   ;; Other symbols from structures, etc.
 	   "C-CC"
 	   "C-CFLAG"
@@ -672,10 +670,6 @@
 	   ;; run-program.lisp
 	   "SGTTYB"
 
-	   ;; Simple streams
-	   "PROT_READ"
-	   "UNIX-MUNMAP"
-
 	   ;; Other symbols
 	   "BLKCNT-T"
 	   "C-CC"

--- a/src/code/unix-glibc2.lisp
+++ b/src/code/unix-glibc2.lisp
@@ -1036,6 +1036,11 @@
 	(values nil (unix-errno))
 	(values result 0))))
 
+(defun unix-munmap (addr length)
+  (declare (type system-area-pointer addr)
+	   (type (unsigned-byte 32) length))
+  (syscall ("munmap" system-area-pointer size-t) t addr length))
+
 (defun unix-msync (addr length flags)
   (declare (type system-area-pointer addr)
 	   (type (unsigned-byte 32) length)