Add implementation of fdprintf, clearenv, and stubs for ttyname_r, *usershell

Change-Id:	I5fe7e8b6ee5edbb49e707c3b6737a58563781fa3
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 791b260..f0e103e 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -437,4 +437,15 @@
 #define getchar_unlocked()	getc_unlocked(stdin)
 #define putchar_unlocked(c)	putc_unlocked(c, stdout)
 
+#ifdef _GNU_SOURCE
+/*
+ * glibc defines dprintf(int, const char*, ...), which is poorly named
+ * and likely to conflict with locally defined debugging printfs
+ * fdprintf is a better name, and some programs that use fdprintf use a
+ * #define fdprintf dprintf for compatibility
+ */
+int fdprintf(int, const char*, ...);
+int vfdprintf(int, const char*, __va_list);
+#endif /* _GNU_SOURCE */
+
 #endif /* _STDIO_H_ */
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index 954f34e..b4f1dda 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -99,6 +99,10 @@
 extern int issetugid(void);
 extern char* getlogin(void);
 extern int getlogin_r(char* name, size_t namesize);
+extern char* getusershell(void);
+extern void setusershell(void);
+extern void endusershell(void);
+
 
 
 /* Macros for access() */
@@ -163,6 +167,8 @@
 extern int optind, opterr, optopt;
 
 extern int isatty(int);
+extern char* ttyname(int);
+extern int ttyname_r(int, char*, size_t);
 
 extern int  acct(const char*  filepath);