Applied vodz' patches #49 and #50 (with a small correction in runshell.c)

#49: I found one memory overflow and memory leak in "ln" applet.
Last patch reduced also 54 bytes. ;)

#50: I found bug in loginutils/Makefile.in.
New patch have also new function to libbb and
aplied this to applets and other cosmetic changes.

include/libbb.h

@@ -321,6 +321,8 @@ void reset_ino_dev_hashtable(void);
 extern size_t xstrlen(const char *string);
 #define strlen(x)   xstrlen(x)
 
+void bb_asprintf(char **string_ptr, const char *format, ...) __attribute__ ((format (printf, 2, 3)));
+
 
 #define FAIL_DELAY    3
 extern void change_identity ( const struct passwd *pw );