Fix definition of environ on Mac OS X (bugzilla: #5412).

lib/replace/libreplace.m4

@@ -222,6 +222,7 @@ AC_CHECK_TYPE(comparison_fn_t,
 
 AC_HAVE_DECL(setenv, [#include <stdlib.h>])
 AC_CHECK_FUNCS(setenv unsetenv)
+AC_HAVE_DECL(environ, [#include <unistd.h>])
 
 AC_CHECK_FUNCS(strnlen)
 AC_CHECK_FUNCS(strtoull __strtoull strtouq strtoll __strtoll strtoq)

lib/replace/replace.h

@@ -182,6 +182,15 @@ char *rep_strndup(const char *s, size_t n);
 size_t rep_strnlen(const char *s, size_t n);
 #endif
 
+#if !HAVE_DECL_ENVIRON
+#ifdef __APPLE__
+#include <crt_externs.h>
+#define environ (*_NSGetEnviron())
+#else
+extern char **environ;
+#endif
+#endif
+
 #ifndef HAVE_SETENV
 #define setenv rep_setenv
 int rep_setenv(const char *name, const char *value, int overwrite);

source3/configure.in

@@ -6210,6 +6210,8 @@ AC_ARG_ENABLE(merged-build,
 [AS_HELP_STRING([--enable-merged-build], [Build Samba 4 as well])], 
 [ enable_merged_build=$enableval ], [ enable_merged_build=auto ])
 
+m4_include(../lib/zlib/zlib.m4)
+
 if test x$enable_merged_build = xauto; then
 	merged_build_possible=yes
 
@@ -6239,7 +6241,6 @@ if test x$enable_merged_build = xyes; then
 	m4_include(samba4.m4)
 fi
 
-m4_include(../lib/zlib/zlib.m4)
 AC_SUBST(ZLIB_LIBS)
 AC_SUBST(ZLIB_OBJS)
 AC_ZLIB([ZLIB_OBJS=""], [