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.

1 files changed, 0 insertions, 2 deletions

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;