[PATCH] Add 'getthrds' declaration check in configure for AIX

[Joel Brobecker <brobecker@adacore.com>]

On newer versions of AIX (6.x and later), this function is actually
declared in procinfo.h, thus causing a compilation warning when we
re-declare it ourselves. This patch adds a configure check for that
function allowing us to declare the function only if the declaration
isn't already present in one of procinfo system header.

gdb/ChangeLog:

        PR gdb/12116:
        * configure.ac: Add getthrds declaration check.
        * configure, config.in: Regenerate.
        * aix-thread.c (getthrds): Declare only if not already declared
        in procinfo.h.  More declaration out of get_signaled_thread to
        global scope.

Tested by rebuilding GDB on AIX 5.3.  Michael Haubenwallner, who
reported the problem, verified that it fixes the problem on AIX 6.1.
Will commit in a couple of days if no objection.

---
 gdb/aix-thread.c |    8 ++++----
 gdb/config.in    |    4 ++++
 gdb/configure    |   15 +++++++++++++++
 gdb/configure.ac |    4 ++++
 4 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/gdb/aix-thread.c b/gdb/aix-thread.c
index 37b798a..c5db262 100644
--- a/gdb/aix-thread.c
+++ b/gdb/aix-thread.c
@@ -58,6 +58,10 @@
 #include <sched.h>
 #include <sys/pthdebug.h>
 
+#if !HAVE_DECL_GETTHRDS
+extern int getthrds (pid_t, struct thrdsinfo64 *, int, pthdb_tid_t *, int);
+#endif
+
 /* Whether to emit debugging output.  */
 static int debug_aix_thread;
 
@@ -647,10 +651,6 @@ get_signaled_thread (void)
   pthdb_tid_t ktid = 0;
   int result = 0;
 
-  /* getthrds(3) isn't prototyped in any AIX 4.3.3 #include file.  */
-  extern int getthrds (pid_t, struct thrdsinfo64 *, 
-		       int, pthdb_tid_t *, int);
-
   while (1)
   {
     if (getthrds (PIDGET (inferior_ptid), &thrinf, 
diff --git a/gdb/config.in b/gdb/config.in
index ccceabf..01ba750 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -118,6 +118,10 @@
    */
 #undef HAVE_DECL_GETOPT
 
+/* Define to 1 if you have the declaration of `getthrds', and to 0 if you
+   don't. */
+#undef HAVE_DECL_GETTHRDS
+
 /* Define to 1 if you have the declaration of `malloc', and to 0 if you don't.
    */
 #undef HAVE_DECL_MALLOC
diff --git a/gdb/configure b/gdb/configure
index 5ee5ce6..ebac1f6 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -12819,6 +12819,21 @@ _ACEOF
 
 fi
 
+# Older versions of AIX do not provide the declaration for the getthrds
+# function (it appears that it was introduced with AIX 6.x).
+ac_fn_c_check_decl "$LINENO" "getthrds" "ac_cv_have_decl_getthrds" "#include <procinfo.h>
+"
+if test "x$ac_cv_have_decl_getthrds" = x""yes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_GETTHRDS $ac_have_decl
+_ACEOF
+
+
 if test "$cross_compiling" = no; then
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether setpgrp takes no argument" >&5
 $as_echo_n "checking whether setpgrp takes no argument... " >&6; }
diff --git a/gdb/configure.ac b/gdb/configure.ac
index d2b75f6..2c708cb 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1069,6 +1069,10 @@ if test -n "$[5]"; then
     [Define to the type of arg 5 for ptrace.])
 fi
 
+# Older versions of AIX do not provide the declaration for the getthrds
+# function (it appears that it was introduced with AIX 6.x).
+AC_CHECK_DECLS(getthrds, [], [], [[#include <procinfo.h>]])
+
 dnl AC_FUNC_SETPGRP does not work when cross compiling
 dnl Instead, assume we will have a prototype for setpgrp if cross compiling.
 if test "$cross_compiling" = no; then
-- 
1.7.1