diff --git a/winsup/cygwin/include/cygwin/acl.h b/winsup/cygwin/include/cygwin/acl.h
index b7cbf03f3..846c49cb6 100644
--- a/winsup/cygwin/include/cygwin/acl.h
+++ b/winsup/cygwin/include/cygwin/acl.h
@@ -33,56 +33,62 @@ extern "C" {
    On one hand, there are only a limited number of SIDs shorter than the normal
    user/group SIDs, on the other hand there are no deny aclent_t entries, so we
    should be fine with 32K aclbuf_t buffers provided by the caller. */
-#define	MIN_ACL_ENTRIES (3)    // minimal acl entries from GETACLCNT
-#define	MAX_ACL_ENTRIES	(2730) // max entries of each type
+#define	MIN_ACL_ENTRIES (3)    /* minimal acl entries from GETACLCNT	    */
+#define	MAX_ACL_ENTRIES	(2730) /* max entries of each type		    */
 
-// Return values of aclcheck(3) in case of error */
+/* Return values of aclcheck(3) in case of error */
 #define GRP_ERROR       (0x1)
 #define USER_ERROR      (0x2)
 #define CLASS_ERROR     (0x3)
 #define OTHER_ERROR     (0x4)
 #define DUPLICATE_ERROR (0x5)
 #define ENTRY_ERROR     (0x6)
-#define MISS_ERROR      (0x7) // which = -1
-#define MEM_ERROR       (0x8) // which = -1
+#define MISS_ERROR      (0x7) /* which = -1 */
+#define MEM_ERROR       (0x8) /* which = -1 */
 
-// Values for entry type of struct acl
-#define USER_OBJ        (0x0001)                // owner
-#define USER            (0x0002)                // additional user
-#define GROUP_OBJ       (0x0004)                // owning group
-#define GROUP           (0x0008)                // additional group
-#define CLASS_OBJ       (0x0010)                // mask entry
-#define OTHER_OBJ       (0x0020)                // others
-#define ACL_DEFAULT     (0x1000)                // default flag
-#define DEF_USER_OBJ    (ACL_DEFAULT|USER_OBJ)  // default owner
-#define DEF_USER        (ACL_DEFAULT|USER)      // default additional user
-#define DEF_GROUP_OBJ   (ACL_DEFAULT|GROUP_OBJ) // default owning group
-#define DEF_GROUP       (ACL_DEFAULT|GROUP)     // default additional group
-#define DEF_CLASS_OBJ   (ACL_DEFAULT|CLASS_OBJ) // default mask entry
-#define DEF_OTHER_OBJ   (ACL_DEFAULT|OTHER_OBJ) // default others
-// Values with equivalent meanings
+/* Values for entry type of struct acl */
+#define USER_OBJ        (0x0001)                /* owner		    */
+#define USER            (0x0002)                /* additional user	    */
+#define GROUP_OBJ       (0x0004)                /* owning group		    */
+#define GROUP           (0x0008)                /* additional group	    */
+#define CLASS_OBJ       (0x0010)                /* mask entry		    */
+#define OTHER_OBJ       (0x0020)                /* others		    */
+#define ACL_DEFAULT     (0x1000)                /* default flag		    */
+#define DEF_USER_OBJ    (ACL_DEFAULT|USER_OBJ)  /* default owner	    */
+#define DEF_USER        (ACL_DEFAULT|USER)      /* default additional user  */
+#define DEF_GROUP_OBJ   (ACL_DEFAULT|GROUP_OBJ) /* default owning group	    */
+#define DEF_GROUP       (ACL_DEFAULT|GROUP)     /* default additional group */
+#define DEF_CLASS_OBJ   (ACL_DEFAULT|CLASS_OBJ) /* default mask entry	    */
+#define DEF_OTHER_OBJ   (ACL_DEFAULT|OTHER_OBJ) /* default others	    */
+/* Values with equivalent meanings */
 #define USER_OWNER      USER_OBJ
 #define GROUP_OWNER     GROUP_OBJ
 #define MASK            CLASS_OBJ
 #define OTHER           OTHER_OBJ
 
 typedef struct acl {
-    int          a_type;    /* entry type */
-    uid_t        a_id;      /* UID | GID  */
+    int          a_type;    /* entry type  */
+    id_t         a_id;      /* UID | GID   */
     mode_t       a_perm;    /* permissions */
 } aclent_t;
 
 #ifndef __INSIDE_CYGWIN__
-int _EXFUN(acl,(const char *path, int cmd, int nentries, aclent_t *aclbufp));
-int _EXFUN(facl,(int fd, int cmd, int nentries, aclent_t *aclbufp));
-int _EXFUN(aclcheck,(aclent_t *aclbufp, int nentries, int *which));
-int _EXFUN(aclsort,(int nentries, int calclass, aclent_t *aclbufp));
-int _EXFUN(acltomode,(aclent_t *aclbufp, int nentries, mode_t *modep));
-int _EXFUN(aclfrommode,(aclent_t *aclbufp, int nentries, mode_t *modep));
-int _EXFUN(acltopbits,(aclent_t *aclbufp, int nentries, mode_t *pbitsp));
-int _EXFUN(aclfrompbits,(aclent_t *aclbufp, int nentries, mode_t *pbitsp));
-char *_EXFUN(acltotext,(aclent_t *aclbufp, int aclcnt));
-aclent_t *_EXFUN(aclfromtext,(char *acltextp, int *aclcnt));
+extern int	 acl (const char *__path, int __cmd, int __nentries,
+		      aclent_t *__aclbufp);
+extern int	 facl (int __fd, int __cmd, int __nentries,
+		       aclent_t *__aclbufp);
+extern int	 aclcheck (aclent_t *__aclbufp, int __nentries, int *__which);
+extern int	 aclsort (int __nentries, int __calclass, aclent_t *__aclbufp);
+extern int	 acltomode (aclent_t *__aclbufp, int __nentries,
+			    mode_t *__modep);
+extern int	 aclfrommode (aclent_t *__aclbufp, int __nentries,
+			      mode_t *__modep);
+extern int	 acltopbits (aclent_t *__aclbufp, int __nentries,
+			     mode_t *__pbitsp);
+extern int	 aclfrompbits (aclent_t *__aclbufp, int __nentries,
+			       mode_t *__pbitsp);
+extern char	*acltotext (aclent_t *__aclbufp, int __aclcnt);
+extern aclent_t *aclfromtext (char *__acltextp, int *__aclcnt);
 #endif
 
 #ifdef __cplusplus