[i686 Linux] Fix undefined ‘__swift_ssize_t’

Author: Kaiede

stdlib/public/SwiftShims/LibcShims.h

@@ -33,7 +33,7 @@ namespace swift { extern "C" {
 
 // This declaration is not universally correct.  We verify its correctness for
 // the current platform in the runtime code.
-#if defined(__linux__) && defined (__arm__)
+#if defined(__linux__) && (defined(__arm__) || defined(__i386__))
 typedef           int __swift_ssize_t;
 #elif defined(_WIN32)
 #if defined(_M_ARM) || defined(_M_IX86)