diff --git a/lib/dictBuilder/zdict.c b/lib/dictBuilder/zdict.c
index 79c522ef3..baaa57153 100644
--- a/lib/dictBuilder/zdict.c
+++ b/lib/dictBuilder/zdict.c
@@ -23,9 +23,13 @@
 /* Unix Large Files support (>4GB) */
 #define _FILE_OFFSET_BITS 64
 #if (defined(__sun__) && (!defined(__LP64__)))   /* Sun Solaris 32-bits requires specific definitions */
+#  ifndef _LARGEFILE_SOURCE
 #  define _LARGEFILE_SOURCE
+#  endif
 #elif ! defined(__LP64__)                        /* No point defining Large file for 64 bit */
+#  ifndef _LARGEFILE64_SOURCE
 #  define _LARGEFILE64_SOURCE
+#  endif
 #endif