Only dllexport during the compilation of iconv.c

ext/iconv/config.w32

@@ -12,6 +12,7 @@ if (PHP_ICONV != "no") {
 		AC_DEFINE("HAVE_LIBICONV", 1, "Define if libiconv is available");
 		AC_DEFINE("PHP_ICONV_IMPL", "\"libiconv\"", "Which iconv implementation to use");
 		AC_DEFINE("ICONV_SUPPORTS_ERRNO", 1, "Whether iconv supports errno or not");
+		ADD_FLAG("CFLAGS_ICONV", "/D PHP_ICONV_EXPORTS ");
 		if (!PHP_ICONV_SHARED) {
 			ADD_DEF_FILE("ext\\iconv\\php_iconv.def");
 		}

ext/iconv/php_iconv.h

@@ -23,8 +23,12 @@
 #define PHP_ICONV_H
 
 #ifdef PHP_WIN32
+#ifdef PHP_ICONV_EXPORTS
 #define PHP_ICONV_API __declspec(dllexport)
 #else
+#define PHP_ICONV_API __declspec(dllimport)
+#endif 
+#else
 #define PHP_ICONV_API
 #endif