diff --git a/textproc/groff/files/patch-lib_math.in.h b/textproc/groff/files/patch-lib_math.in.h
new file mode 100644
index 000000000000..b5e2d6a81837
--- /dev/null
+++ b/textproc/groff/files/patch-lib_math.in.h
@@ -0,0 +1,11 @@
+--- lib/math.in.h.orig	2018-12-23 14:34:15 UTC
++++ lib/math.in.h
+@@ -34,7 +34,7 @@
+ #endif
+ 
+ #ifndef _GL_INLINE_HEADER_BEGIN
+- #error "Please include config.h first."
++# include "config.h"
+ #endif
+ _GL_INLINE_HEADER_BEGIN
+ #ifndef _GL_MATH_INLINE