Define SSIZE_MAX conditionally on Windows

Author: oschwald

Changes.md

@@ -1,3 +1,9 @@
+## 1.9.1
+
+* `SSIZE_MAX` is now defined conditionally on Windows. The 1.9.0
+  release would cause a redefinition warning when compiled with MinGW.
+  Reported by Andreas Vögele. GitHub #338.
+
 ## 1.9.0 - 2024-01-09
 
 * On very large databases, the calculation to determine the search tree

src/maxminddb.c

@@ -23,7 +23,9 @@
 #endif
 #include <windows.h>
 #include <ws2ipdef.h>
+#ifndef SSIZE_MAX
 #define SSIZE_MAX INTPTR_MAX
+#endif
 typedef ADDRESS_FAMILY sa_family_t;
 #else
 #include <arpa/inet.h>