Index: src/bin/jp2/convert.c
--- src/bin/jp2/convert.c.orig
+++ src/bin/jp2/convert.c
@@ -662,7 +662,7 @@ static int tga_readheader(FILE *fp, unsigned int *bits
     return 1;
 }
 
-#ifdef OPJ_BIG_ENDIAN
+#if defined(OPJ_BIG_ENDIAN) && !defined(swap16)
 
 static INLINE OPJ_UINT16 swap16(OPJ_UINT16 x)
 {