* libmisc/limits.c: Avoid implicit conversion of integer to

boolean.
	* libmisc/basename.c: Avoid implicit conversion of pointer to
	boolean.
	* libmisc/basename.c, lib/prototypes.h (Basename): Return a
	constant string.
	* libmisc/basename.c, libmisc/obscure.c, lib/prototypes.h,
	libmisc/xmalloc.c, libmisc/getdate.h, libmisc/system.c,
	libmisc/getgr_nam_gid.c, libmisc/failure.c, libmisc/valid.c: Add
	splint annotations.
	* libmisc/chowndir.c: Avoid memory leak.
	* libmisc/chowndir.c: Do not check *printf/*puts return value.
	* libmisc/chowntty.c: Avoid implicit conversion between integer
	types.
	* libmisc/obscure.c: Return a bool when possible instead of int.
	* libmisc/shell.c: Do not check *printf/*puts return value.
	* libmisc/shell.c: Do not check execle return value.
	* libmisc/setupenv.c: Avoid implicit conversion between integer
	types.
	* libmisc/xmalloc.c: size should not be zero to avoid returning
	NULL pointers.
	* libmisc/hushed.c: Do not check *printf/*puts return value.
	* libmisc/system.c: Avoid implicit conversion of integer to
	boolean. safe_system last argument is a boolean.
	* libmisc/system.c: Check return value of dup2.
	* libmisc/system.c: Do not check *printf/*puts return value.
	* libmisc/system.c: Do not check execve return value. 
	* libmisc/salt.c: Do not check *printf/*puts return value.
	* libmisc/loginprompt.c: Do not check gethostname return value.
	* libmisc/find_new_gid.c, libmisc/find_new_uid.c: Do not check
	gr_rewind/pw_rewind return value.
	* libmisc/ttytype.c: Limit the number of parsed characters in the
	sscanf format.
	* libmisc/ttytype.c: Test if a type was really read.
	* libmisc/sub.c: Do not check *printf/*puts return value.
	* libmisc/sub.c: Avoid implicit conversion of integer to boolean.
	* src/userdel.c: Fix typo in comment.
	* src/userdel.c: Avoid implicit conversion of boolean to integer.
	* src/userdel.c: safe_system last argument is a boolean.
	* src/newusers.c: Avoid implicit conversion of boolean to integer.
	* src/newusers.c: Avoid implicit conversion of integer to boolean.
	* src/usermod.c: Add brackets.
	* src/usermod.c: Avoid implicit conversion of characters or
	integers to booleans.
	* src/vipw.c: Avoid implicit conversion of integer to boolean.
	* src/su.c: Avoid implicit conversion of integer to boolean.
	* src/su.c: Add brackets.
	* src/useradd.c: Avoid implicit conversion of characters or
	integers to booleans.

lib/prototypes.h

@@ -57,7 +57,7 @@
 #include "defines.h"
 #include "commonio.h"
 
-extern char *Prog;
+extern /*@observer@*/ const char *Prog;
 
 /* addgrps.c */
 #if defined (HAVE_SETGROUPS) && ! defined (USE_PAM)
@@ -72,7 +72,7 @@ extern int isexpired (const struct passwd *, /*@null@*/const struct spwd *);
 
 /* basename() renamed to Basename() to avoid libc name space confusion */
 /* basename.c */
-extern char *Basename (char *str);
+extern /*@observer@*/const char *Basename (char *str);
 
 /* chowndir.c */
 extern int chown_tree (const char *root,
@@ -156,7 +156,7 @@ extern int find_new_uid (bool sys_user,
 extern int get_gid (const char *gidstr, gid_t *gid);
 
 /* getgr_nam_gid.c */
-extern /*@null@*/struct group *getgr_nam_gid (const char *grname);
+extern /*@null@*/struct group *getgr_nam_gid (/*@null@*/const char *grname);
 
 /* getlong.c */
 extern int getlong (const char *numstr, /*@out@*/long int *result);
@@ -340,8 +340,8 @@ extern int shell (const char *file, /*@null@*/const char *arg, char *const envp[
 /* system.c */
 extern int safe_system (const char *command,
                         const char *argv[],
-                        const char *env[],
-                        int ignore_stderr);
+                        /*@null@*/const char *env[],
+                        bool ignore_stderr);
 
 /* strtoday.c */
 extern long strtoday (const char *);
@@ -391,9 +391,9 @@ extern int setutmpx (struct utmpx *utx);
 extern bool valid (const char *, const struct passwd *);
 
 /* xmalloc.c */
-extern /*@maynotreturn@*/ /*@out@*//*@only@*/char *xmalloc (size_t size)
+extern /*@maynotreturn@*/ /*@only@*//*@out@*//*@notnull@*/char *xmalloc (size_t size)
   /*@ensures MaxSet(result) == (size - 1); @*/;
-extern /*@maynotreturn@*/ /*@only@*/char *xstrdup (const char *);
+extern /*@maynotreturn@*/ /*@only@*//*@notnull@*/char *xstrdup (const char *);
 
 /* xgetpwnam.c */
 extern /*@null@*/ /*@only@*/struct passwd *xgetpwnam (const char *);