Index: subversion/include/private/svn_compat.h
===================================================================
--- subversion/include/private/svn_compat.h	(revision 0)
+++ subversion/include/private/svn_compat.h	(revision 0)
@@ -0,0 +1,58 @@
+/**
+ * @copyright
+ * ====================================================================
+ * Copyright (c) 2006 CollabNet.  All rights reserved.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution.  The terms
+ * are also available at http://subversion.tigris.org/license-1.html.
+ * If newer versions of this license are posted there, you may use a
+ * newer version instead, at your option.
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals.  For exact contribution history, see the revision
+ * history and logs, available at http://subversion.tigris.org/.
+ * ====================================================================
+ * @endcopyright
+ *
+ * @file svn_compat.h
+ * @brief Compatibility macros and functions.
+ * @since New in 1.5.0.
+ */
+
+#ifndef SVN_COMPAT_H
+#define SVN_COMPAT_H
+
+#include <apr_version.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * Check at compile time if the APR version is at least a certain
+ * level.
+ * @param major The major version component of the version checked
+ * for (e.g., the "1" of "1.3.0").
+ * @param minor The minor version component of the version checked
+ * for (e.g., the "3" of "1.3.0").
+ * @param patch The patch level component of the version checked
+ * for (e.g., the "0" of "1.3.0").
+ *
+ * @since New in 1.5.0
+ */
+#ifdef APR_VERSION_AT_LEAST /* Introduced in APR 1.3.0 */
+#define SVN_APR_VERSION_AT_LEAST APR_VERSION_AT_LEAST
+#else
+#define SVN_APR_VERSION_AT_LEAST(major,minor,patch)                  \
+(((major) < APR_MAJOR_VERSION)                                       \
+ || ((major) == APR_MAJOR_VERSION && (minor) < APR_MINOR_VERSION)    \
+ || ((major) == APR_MAJOR_VERSION && (minor) == APR_MINOR_VERSION && \
+     (patch) <= APR_PATCH_VERSION))
+#endif /* APR_VERSION_AT_LEAST */
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* SVN_COMPAT_H */
Index: subversion/include/private/svn_atomic.h
===================================================================
--- subversion/include/private/svn_atomic.h	(revision 21572)
+++ subversion/include/private/svn_atomic.h	(working copy)
@@ -26,6 +26,7 @@
 #include <apr_atomic.h>
 
 #include "svn_error.h"
+#include "private/svn_compat.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -40,39 +41,39 @@
  */
 
 /** The type used by all the other atomic operations. */
-#if APR_MAJOR_VERSION > 0
+#if SVN_APR_VERSION_AT_LEAST(1, 0, 0)
 #define svn_atomic_t apr_uint32_t
 #else
 #define svn_atomic_t apr_atomic_t
-#endif /* APR_MAJOR_VERSION */
+#endif
 
 /** Atomically read an #svn_atomic_t from memory. */
-#if APR_MAJOR_VERSION > 0
+#if SVN_APR_VERSION_AT_LEAST(1, 0, 0)
 #define svn_atomic_read(mem) apr_atomic_read32((mem))
 #else
 #define svn_atomic_read(mem) apr_atomic_read((mem))
-#endif /* APR_MAJOR_VERSION */
+#endif
 
 /** Atomically set an #svn_atomic_t in memory. */
-#if APR_MAJOR_VERSION > 0
+#if SVN_APR_VERSION_AT_LEAST(1, 0, 0)
 #define svn_atomic_set(mem, val) apr_atomic_set32((mem), (val))
 #else
 #define svn_atomic_set(mem, val) apr_atomic_set((mem), (val))
-#endif /* APR_MAJOR_VERSION */
+#endif
 
 /** Atomically increment an #svn_atomic_t. */
-#if APR_MAJOR_VERSION > 0
+#if SVN_APR_VERSION_AT_LEAST(1, 0, 0)
 #define svn_atomic_inc(mem) apr_atomic_inc32(mem)
 #else
 #define svn_atomic_inc(mem) apr_atomic_inc(mem)
-#endif /* APR_MAJOR_VERSION */
+#endif
 
 /** Atomically decrement an #svn_atomic_t. */
-#if APR_MAJOR_VERSION > 0
+#if SVN_APR_VERSION_AT_LEAST(1, 0, 0)
 #define svn_atomic_dec(mem) apr_atomic_dec32(mem)
 #else
 #define svn_atomic_dec(mem) apr_atomic_dec(mem)
-#endif /* APR_MAJOR_VERSION */
+#endif
 
 /** 
  * Atomic compare-and-swap.
@@ -85,13 +86,13 @@
  *       that on some platforms, the CAS function is implemented in a
  *       way that is incompatible with the other atomic operations.
  */
-#if APR_MAJOR_VERSION > 0
+#if SVN_APR_VERSION_AT_LEAST(1, 0, 0)
 #define svn_atomic_cas(mem, with, cmp) \
     apr_atomic_cas32((mem), (with), (cmp))
 #else
 #define svn_atomic_cas(mem, with, cmp) \
     apr_atomic_cas((mem), (with), (cmp))
-#endif /* APR_MAJOR_VERSION */
+#endif
 /** @} */
 
 /**
Index: subversion/libsvn_subr/hash.c
===================================================================
--- subversion/libsvn_subr/hash.c	(revision 21572)
+++ subversion/libsvn_subr/hash.c	(working copy)
@@ -32,6 +32,7 @@
 #include "svn_sorts.h"
 #include "svn_io.h"
 #include "svn_pools.h"
+#include "private/svn_compat.h"
 
 
 
@@ -437,9 +438,7 @@
 svn_error_t *
 svn_hash_clear(apr_hash_t *hash)
 {
-/* The APR_VERSION_AT_LEAST() macro is new in APR 1.3.0, which also
-   happens to be the minimum version we require. */
-#ifdef APR_VERSION_AT_LEAST /* 1.3.0 */
+#if SVN_APR_VERSION_AT_LEAST(1, 3, 0)
   apr_hash_clear(hash);
 #else
   apr_hash_index_t *hi;