diff --git a/CMakeLists.txt b/CMakeLists.txt
index e0e1149f3..899065299 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -660,6 +660,8 @@ CHECK_TYPE_SIZE("uchar"		 SIZEOF_UCHAR)
 CHECK_TYPE_SIZE("int64_t"	 SIZEOF_INT64_T)
 CHECK_TYPE_SIZE("uint64_t"	 SIZEOF_UINT64_T)
 
+SET(HAVE_SSIZE_T SIZEOF_SSIZE_T CACHE STRING "")
+
 # Check for various functions. 
 CHECK_FUNCTION_EXISTS(fsync	HAVE_FSYNC)
 CHECK_FUNCTION_EXISTS(strlcat 	HAVE_STRLCAT)