diff -ur a/gsl_inline.h b/gsl_inline.h
--- a/gsl_inline.h	2024-06-05 08:59:43.655369544 -0500
+++ b/gsl_inline.h	2024-06-05 09:00:02.707862690 -0500
@@ -49,7 +49,7 @@
 #ifdef HAVE_INLINE
 #  if defined(__GNUC_STDC_INLINE__) || defined(GSL_C99_INLINE) || defined(HAVE_C99_INLINE)
 #    define INLINE_DECL inline  /* use C99 inline */
-#    define INLINE_FUN inline
+#    define INLINE_FUN static inline
 #  else
 #    define INLINE_DECL         /* use GNU extern inline */
 #    define INLINE_FUN extern inline