From 7e50a3977327c52e9e04f9cf3ac1cd0a54f042b2 Mon Sep 17 00:00:00 2001
From: zwelch <zwelch@b42882b7-edfa-0310-969c-e2dbd0fdcd60>
Date: Wed, 6 May 2009 07:17:57 +0000
Subject: [PATCH] Add autoconf check to determine where environ should be
 declared.

git-svn-id: svn://svn.berlios.de/openocd/trunk@1610 b42882b7-edfa-0310-969c-e2dbd0fdcd60
---
 configure.in     | 31 +++++++++++++++++++++++++++++++
 src/helper/jim.c |  2 +-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/configure.in b/configure.in
index 3b1d49e4f..50c149a83 100644
--- a/configure.in
+++ b/configure.in
@@ -784,6 +784,37 @@ AC_PROG_CC
 AM_PROG_CC_C_O
 AC_PROG_RANLIB
 
+# Look for environ alternatives.  Possibility #1: is environ in unistd.h?
+AC_MSG_CHECKING([for environ in unistd.h])
+AC_COMPILE_IFELSE([
+#define _GNU_SOURCE
+#include <unistd.h>
+int main(int argc, char **argv) { char **ep = environ; }
+  ], [
+    AC_MSG_RESULT([yes])
+    has_environ=yes
+  ], [
+    AC_MSG_RESULT([no])
+
+    # Possibility #2: can environ be found in an available library?
+    AC_MSG_CHECKING([for extern environ])
+    AC_LINK_IFELSE([
+extern char **environ;
+int main(int argc, char **argv) { char **ep = environ; }
+      ], [
+        AC_DEFINE(NEED_ENVIRON_EXTERN, [1], [Must declare 'environ' to use it.])
+        has_environ=yes
+      ], [
+        has_environ=no
+      ])
+    AC_MSG_RESULT([${has_environ}])
+  ])
+
+if test "${has_environ}" != "yes" ; then
+     AC_MSG_FAILURE([Could find 'environ' in unistd.h or available libraries.]) 
+fi
+
+
 # set default gcc warnings
 GCC_WARNINGS="-Wall -Wstrict-prototypes -Wformat-security"
 if test "${gcc_wextra}" = yes; then
diff --git a/src/helper/jim.c b/src/helper/jim.c
index 32c146fa8..05236fc20 100644
--- a/src/helper/jim.c
+++ b/src/helper/jim.c
@@ -11984,7 +11984,7 @@ static int Jim_EnvCoreCommand(Jim_Interp *interp, int argc,
 
     if (argc == 1) {
 
-#if !defined(HAVE_UNISTD_H) || !defined(__GNU_LIBRARY__)
+#ifdef NEED_ENVIRON_EXTERN
         extern char **environ;
 #endif