Darwin seems to like this much better.

ext/curl/interface.c

@@ -52,6 +52,9 @@
 #include "ext/standard/url.h"
 #include "php_curl.h"
 
+int  le_curl;
+int  le_curl_multi_handle;
+
 static void _php_curl_close(zend_rsrc_list_entry *rsrc TSRMLS_DC);
 
 #define SAVE_CURL_ERROR(__handle, __err) (__handle)->err.no = (int) __err;

ext/curl/php_curl.h

@@ -51,9 +51,9 @@ extern zend_module_entry curl_module_entry;
 #define PHP_CURL_BINARY 6
 #define PHP_CURL_IGNORE 7
 
-int  le_curl;
+extern int  le_curl;
 #define le_curl_name "cURL handle"
-int  le_curl_multi_handle;
+extern int  le_curl_multi_handle;
 #define le_curl_multi_handle_name "cURL Multi Handle"
 
 PHP_MINIT_FUNCTION(curl);