getpwnam.3: Rename arguments to getpwnam_r() and getpwuid_r()

s/pwbuf/pwd/ and s/pwbufp/result/, for consistency
with POSIX.1 argument names.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man3/getpwnam.3

@@ -41,13 +41,13 @@ getpwnam, getpwnam_r, getpwuid, getpwuid_r \- get password file entry
 .sp
 .BI "struct passwd *getpwuid(uid_t " uid );
 .sp
-.BI "int getpwnam_r(const char *" name ", struct passwd *" pwbuf ,
+.BI "int getpwnam_r(const char *" name ", struct passwd *" pwd ,
 .br
-.BI "            char *" buf ", size_t " buflen ", struct passwd **" pwbufp );
+.BI "            char *" buf ", size_t " buflen ", struct passwd **" result );
 .sp
-.BI "int getpwuid_r(uid_t " uid ", struct passwd *" pwbuf ,
+.BI "int getpwuid_r(uid_t " uid ", struct passwd *" pwd ,
 .br
-.BI "            char *" buf ", size_t " buflen ", struct passwd **" pwbufp );
+.BI "            char *" buf ", size_t " buflen ", struct passwd **" result );
 .fi
 .sp
 .in -4n
@@ -86,7 +86,7 @@ and
 functions obtain the same information, but store the retrieved
 .I passwd
 structure in the space pointed to by
-.IR pwbuf .
+.IR pwd .
 This
 .I passwd
 structure contains pointers to strings, and these strings
@@ -96,7 +96,7 @@ of size
 .IR buflen .
 A pointer to the result (in case of success) or NULL (in case no entry
 was found or an error occurred) is stored in
-.IR *pwbufp .
+.IR *result .
 .PP
 The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:
 .sp
@@ -148,14 +148,14 @@ On success,
 and
 .BR getpwuid_r ()
 return zero, and set
-.IR *pwbufp
+.IR *result
 to
-.IR pwbuf .
+.IR pwd .
 If no matching password record was found,
 these functions return 0 and store NULL in
-.IR *pwbufp .
+.IR *result .
 In case of error, an error number is returned, and NULL is stored in
-.IR *pwbufp .
+.IR *result .
 .SH ERRORS
 .TP
 .BR 0 " or " ENOENT " or " ESRCH " or " EBADF " or " EPERM " or ... "