vlc_memalign(): osx 10.5 doesn't have posix_memalign()

include/vlc_common.h

@@ -886,10 +886,34 @@ static inline void SetQWLE (void *p, uint64_t qw)
 VLC_API bool vlc_ureduce( unsigned *, unsigned *, uint64_t, uint64_t, uint64_t );
 
 /* Aligned memory allocator */
+#ifdef __APPLE__
+#include <AvailabilityMacros.h>
+#endif
+
 #ifdef WIN32
 # include <malloc.h>
 # define vlc_memalign(align, size) (__mingw_aligned_malloc(size, align))
 # define vlc_free(base)            (__mingw_aligned_free(base))
+#elif defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
+static inline void *vlc_memalign(size_t align, size_t size)
+{
+    long diff;
+    void *ptr;
+
+    ptr = malloc(size+align);
+    if(!ptr)
+        return ptr;
+    diff = ((-(long)ptr - 1)&(align-1)) + 1;
+    ptr  = (char*)ptr + diff;
+    ((char*)ptr)[-1]= diff;
+    return ptr;
+}
+
+static void vlc_free(void *ptr)
+{
+    if (ptr)
+        free((char*)ptr - ((char*)ptr)[-1]);
+}
 #else
 static inline void *vlc_memalign(size_t align, size_t size)
 {