diff --git a/third-party/libnatpmp/Makefile.am b/third-party/libnatpmp/Makefile.am
index 923ab169d..3fca7d53c 100644
--- a/third-party/libnatpmp/Makefile.am
+++ b/third-party/libnatpmp/Makefile.am
@@ -1,7 +1,5 @@
 noinst_LIBRARIES = libnatpmp.a
 
-AM_CPPFLAGS = -DENABLE_STRNATPMPERR
-
 libnatpmp_a_SOURCES = \
     getgateway.c \
     natpmp.c
diff --git a/third-party/libnatpmp/natpmp.c b/third-party/libnatpmp/natpmp.c
index 9ea3a053e..8668cf11d 100644
--- a/third-party/libnatpmp/natpmp.c
+++ b/third-party/libnatpmp/natpmp.c
@@ -267,7 +267,6 @@ int readnatpmpresponseorretry(natpmp_t * p, natpmpresp_t * response)
 	return n;
 }
 
-#ifdef ENABLE_STRNATPMPERR
 const char * strnatpmperr(int r)
 {
 	const char * s;
@@ -335,5 +334,4 @@ const char * strnatpmperr(int r)
 	}
 	return s;
 }
-#endif
 
diff --git a/third-party/libnatpmp/natpmp.h b/third-party/libnatpmp/natpmp.h
index 9470543f7..ac7ec95f6 100644
--- a/third-party/libnatpmp/natpmp.h
+++ b/third-party/libnatpmp/natpmp.h
@@ -179,8 +179,6 @@ LIBSPEC int getnatpmprequesttimeout(natpmp_t * p, struct timeval * timeout);
  * NATPMP_ERR_UNDEFINEDERROR */
 LIBSPEC int readnatpmpresponseorretry(natpmp_t * p, natpmpresp_t * response);
 
-#ifdef ENABLE_STRNATPMPERR
 LIBSPEC const char * strnatpmperr(int t);
-#endif
 
 #endif