[patch] Check readlink during configuring gdbserver

[Yao Qi <yao at codesourcery dot com>]

I tried to build gdbserver as host=i686-mingw32 on linux, but get the
following error,

cc1: warnings being treated as errors
../gdb/gdb/gdbserver/hostio.c: In function 'handle_readlink':
../gdb/gdb/gdbserver/hostio.c:475: error: implicit declaration of
function 'readlink'

Even I remove -Werror temporarily, `readlink' can't be found during
linking,

hostio.o: In function `handle_readlink':
../gdb/gdb/gdbserver/hostio.c:475: undefined reference to `_readlink'

This patch is to add `readlink' in AC_CHECK_FUNCS, to check it
during configure.  OK to apply?

-- 
Yao (éå)

gdb/gdbserver:
2012-02-08  Yao Qi  <yao@codesourcery.com>

	* configure.ac: Check for readlink.
	* configure, config.in: Regenerated.
	* hostio.c (handle_readlink) [!HAVE_READLINK]: Write error in packet.
---
 gdb/gdbserver/config.in    |    3 +++
 gdb/gdbserver/configure    |    2 +-
 gdb/gdbserver/configure.ac |    2 +-
 gdb/gdbserver/hostio.c     |    5 +++++
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/gdb/gdbserver/config.in b/gdb/gdbserver/config.in
index a9472ea..7fa3b5b 100644
--- a/gdb/gdbserver/config.in
+++ b/gdb/gdbserver/config.in
@@ -128,6 +128,9 @@
 /* Define to 1 if you have the `pwrite' function. */
 #undef HAVE_PWRITE
 
+/* Define to 1 if you have the `readlink' function. */
+#undef HAVE_READLINK
+
 /* Define to 1 if you have the <sgtty.h> header file. */
 #undef HAVE_SGTTY_H
 
diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index d92a00f..e251844 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -4163,7 +4163,7 @@ fi
 
 done
 
-for ac_func in pread pwrite pread64
+for ac_func in pread pwrite pread64 readlink
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/gdb/gdbserver/configure.ac b/gdb/gdbserver/configure.ac
index 30666ec..7c86cd4 100644
--- a/gdb/gdbserver/configure.ac
+++ b/gdb/gdbserver/configure.ac
@@ -43,7 +43,7 @@ AC_CHECK_HEADERS(sgtty.h termio.h termios.h sys/reg.h string.h dnl
 		 errno.h fcntl.h signal.h sys/file.h malloc.h dnl
 		 sys/ioctl.h netinet/in.h sys/socket.h netdb.h dnl
 		 netinet/tcp.h arpa/inet.h sys/wait.h)
-AC_CHECK_FUNCS(pread pwrite pread64)
+AC_CHECK_FUNCS(pread pwrite pread64 readlink)
 AC_REPLACE_FUNCS(memmem vasprintf vsnprintf)
 
 # Check for UST
diff --git a/gdb/gdbserver/hostio.c b/gdb/gdbserver/hostio.c
index 34e4fa8..b1b104b 100644
--- a/gdb/gdbserver/hostio.c
+++ b/gdb/gdbserver/hostio.c
@@ -459,6 +459,8 @@ handle_unlink (char *own_buf)
 static void
 handle_readlink (char *own_buf, int *new_packet_len)
 {
+#if defined (HAVE_READLINK)
   char filename[PATH_MAX], linkname[PATH_MAX];
   char *p;
   int ret, bytes_sent;
@@ -485,6 +487,9 @@ handle_readlink (char *own_buf, int *new_packet_len)
      to return a partial response, but simply fail.  */
   if (bytes_sent < ret)
     sprintf (own_buf, "F-1,%x", FILEIO_ENAMETOOLONG);
+#else
+  hostio_packet_error (own_buf);
+#endif
 }
 
 /* Handle all the 'F' file transfer packets.  */
-- 
1.7.0.4