getdents.2: s/dirent/linux_dirent/

The structure isn't currently defined in glibc headers, and the kernel
name of the structure is 'linux_dirent' (as was already used in some,
but not all, places in this page).

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

man2/getdents.2

@@ -35,7 +35,7 @@ getdents \- get directory entries
 .B #include <linux/unistd.h>
 .B #include <errno.h>
 
-.BI "int getdents(unsigned int " fd ", struct dirent *" dirp ,
+.BI "int getdents(unsigned int " fd ", struct linux_dirent *" dirp ,
 .BI "             unsigned int " count );
 .fi
 .SH DESCRIPTION
@@ -48,7 +48,7 @@ This page documents the bare kernel system call interface.
 The system call
 .BR getdents ()
 reads several
-.I dirent
+.I linux_dirent
 structures from the directory
 referred to by the open file descriptor
 .I fd
@@ -59,15 +59,15 @@ The argument
 is the size of the memory area.
 .PP
 The
-.I dirent
+.I linux_dirent
 structure is declared as follows:
 .PP
 .in +4n
 .nf
 struct linux_dirent {
     unsigned long  d_ino;     /* Inode number */
-    unsigned long  d_off;     /* Offset to next \fIdirent\fP */
-    unsigned short d_reclen;  /* Length of this \fIdirent\fP */
+    unsigned long  d_off;     /* Offset to next \fIlinux_dirent\fP */
+    unsigned short d_reclen;  /* Length of this \fIlinux_dirent\fP */
     char           d_name []; /* Filename (null-terminated) */
                         /* length is actually (d_reclen \- 2 \-
                            offsetof(struct linux_dirent, d_name) */
@@ -83,10 +83,10 @@ struct linux_dirent {
 is an inode number.
 .I d_off
 is the distance from the start of the directory to the start of the next
-.IR dirent .
+.IR linux_dirent .
 .I d_reclen
 is the size of this entire
-.IR dirent .
+.IR linux_dirent .
 .I d_name
 is a null-terminated filename.