Fix ssize_t types.
When we don't find them, don't try to use them to define them.
From Andrew Molyneux <andrew@molyneuxfamily.co.uk>.
diff --git a/cmake-config.h.in b/cmake-config.h.in
index d11432d..1ba9c04 100644
--- a/cmake-config.h.in
+++ b/cmake-config.h.in
@@ -48,11 +48,11 @@
#define VERSION "@VERSION@"
#ifndef HAVE_SSIZE_T_LIBZIP
-# if SSIZE_T_LIBZIP == INT_LIBZIP
+# if SIZE_T_LIBZIP == INT_LIBZIP
typedef int ssize_t;
-# elif SSIZE_T_LIBZIP == LONG_LIBZIP
+# elif SIZE_T_LIBZIP == LONG_LIBZIP
typedef long ssize_t;
-# elif SSIZE_T_LIBZIP == LONG_LONG_LIBZIP
+# elif SIZE_T_LIBZIP == LONG_LONG_LIBZIP
typedef long long ssize_t;
# else
#error no suitable type for ssize_t found
