Index: head/audio/fasttracker2/Makefile
===================================================================
--- head/audio/fasttracker2/Makefile
+++ head/audio/fasttracker2/Makefile
@@ -18,6 +18,7 @@
 LICENSE_FILE_CC-BY-NC-SA-4.0=	${WRKSRC}/src/gfxdata/bmp/LICENSE.txt
 
 USES=		dos2unix iconv:wchar_t localbase:ldflags sdl zip
+USE_CSTD=	c99
 USE_SDL=	sdl2
 
 WRKSRC=		${WRKDIR}/ft2-clone-code