diff --git a/src/frontend_common/config.h b/src/frontend_common/config.h
index 8b0599cc33..ed817a78b8 100644
--- a/src/frontend_common/config.h
+++ b/src/frontend_common/config.h
@@ -7,7 +7,12 @@
 #include <string>
 #include "common/settings.h"
 
-#define SI_NO_CONVERSION
+// May be defined on command line by system provided packages (FreeBSD devel/simpleini)
+// but if building from source, it will not be defined, so just do it conditionally.
+// Should probably define on CMake anyways but eh
+#ifndef SI_NO_CONVERSION
+#   define SI_NO_CONVERSION 1
+#endif
 #include <SimpleIni.h>
 #include <boost/algorithm/string/replace.hpp>