pinky,who: remove redeclarations of ttyname

Given that `ttyname` is already conditionally declared in src/system.h,
other declarations are redundant and problematic for example in ChromeOS
which has a new FORTIFY implementation that, as an artifact of how it's
implemented, causes the compiler to complain if certain standard library
functions are redeclared without special compiler-specific attributes.

* src/pinky.c: Remove declaration (which was unused anyway).
* src/who.c: Remove declaration.
* src/system.h (getlogin, getuid, geteuid, getgrgid, getpwuid, ttyname):
Add the parameter type to the declarations to avoid warnings when these
backup declarations are used.

3 files changed, 6 insertions, 10 deletions

diff --git a/src/pinky.c b/src/pinky.c
index 68566fdc2..76856090a 100644
--- a/src/pinky.c
+++ b/src/pinky.c
@@ -37,8 +37,6 @@
   proper_name ("David MacKenzie"), \
   proper_name ("Kaveh Ghazi")
 
-char *ttyname (int);
-
 /* If true, display the hours:minutes since each user has touched
    the keyboard, or blank if within the last minute, or days followed
    by a 'd' if not within the last day. */
diff --git a/src/system.h b/src/system.h
index 986a6c786..1b7a0fbb3 100644
--- a/src/system.h
+++ b/src/system.h
@@ -197,23 +197,23 @@ select_plural (uintmax_t n)
 #define STRNCMP_LIT(s, lit) strncmp (s, "" lit "", sizeof (lit) - 1)
 
 #if !HAVE_DECL_GETLOGIN
-char *getlogin ();
+char *getlogin (void);
 #endif
 
 #if !HAVE_DECL_TTYNAME
-char *ttyname ();
+char *ttyname (int);
 #endif
 
 #if !HAVE_DECL_GETEUID
-uid_t geteuid ();
+uid_t geteuid (void);
 #endif
 
 #if !HAVE_DECL_GETPWUID
-struct passwd *getpwuid ();
+struct passwd *getpwuid (uid_t);
 #endif
 
 #if !HAVE_DECL_GETGRGID
-struct group *getgrgid ();
+struct group *getgrgid (gid_t);
 #endif
 
 /* Interix has replacements for getgr{gid,nam,ent}, that don't
@@ -235,7 +235,7 @@ struct group *getgrgid ();
 #endif
 
 #if !HAVE_DECL_GETUID
-uid_t getuid ();
+uid_t getuid (void);
 #endif
 
 #include "xalloc.h"
diff --git a/src/who.c b/src/who.c
index c6fc4dc4b..f56c71833 100644
--- a/src/who.c
+++ b/src/who.c
@@ -96,8 +96,6 @@
 # define UT_ID(U) "??"
 #endif
 
-char *ttyname (int);
-
 /* If true, attempt to canonicalize hostnames via a DNS lookup. */
 static bool do_lookup;