diff --git a/misc/goffice0.10/patches/patch-goffice_math_go-dtoa.c b/misc/goffice0.10/patches/patch-goffice_math_go-dtoa.c
new file mode 100644
index 000000000000..e724335763b4
--- /dev/null
+++ b/misc/goffice0.10/patches/patch-goffice_math_go-dtoa.c
@@ -0,0 +1,20 @@
+$NetBSD: patch-goffice_math_go-dtoa.c,v 1.1 2015/08/04 11:58:51 he Exp $
+
+Ensure frexpl() is declared on NetBSD before 6.99.17.
+
+--- goffice/math/go-dtoa.c.orig	2014-04-30 00:44:52.000000000 +0000
++++ goffice/math/go-dtoa.c
+@@ -43,6 +43,13 @@ typedef GString FAKE_FILE;
+ #define go_finitel isfinite
+ #endif
+ 
++#if defined(__NetBSD__) 
++#if (__NetBSD_Version__ <= 699001700)
++/* in <math.h> in newer NetBSDs, should already be included */
++#else
++extern long double frexpl(long double, int*);
++#endif
++#endif /* __NetBSD__ */
+ 
+ /* musl code starts here */
+