https://bugs.gentoo.org/737236

--- a/src/hscurl.c
+++ b/src/hscurl.c
@@ -11,6 +11,9 @@
 #define ENABLE_PIPELINING
 #endif
 
+/* workaround for https://bugs.gentoo.org/737236 */
+#include "cabal_macros.h"
+
 enum RESULT_CODES
   {
     RESULT_OK = 0,
@@ -46,6 +49,10 @@ struct UrlData
 
 static int debug = 0;
 #ifndef _WIN32
+#ifndef PACKAGE_VERSION
+/* workaround for https://bugs.gentoo.org/737236 */
+#    define PACKAGE_VERSION CURRENT_PACKAGE_VERSION
+#endif
 static const char user_agent[] =
   "darcs/" PACKAGE_VERSION " libcurl/" LIBCURL_VERSION;
 #else