diff --git a/lib/src/query.c b/lib/src/query.c
index 6293bd9f..eb4e906c 100644
--- a/lib/src/query.c
+++ b/lib/src/query.c
@@ -1,3 +1,8 @@
+/*
+ * On NetBSD, defining standard requirements like this removes symbols
+ * from the namespace; however, we need non-standard symbols for
+ * endian.h.
+ */
 #if defined(__NetBSD__) && defined(_POSIX_C_SOURCE)
 #undef _POSIX_C_SOURCE
 #endif