Fix compilation with iconv on FreeBSD
diff --git a/src/stdlib/SDL_iconv.c b/src/stdlib/SDL_iconv.c
index 9e6ea70..f360aa2 100644
--- a/src/stdlib/SDL_iconv.c
+++ b/src/stdlib/SDL_iconv.c
@@ -31,6 +31,10 @@
#include "SDL_endian.h"
#if defined(HAVE_ICONV) && defined(HAVE_ICONV_H)
+#ifdef __FreeBSD__
+/* Define LIBICONV_PLUG to use iconv from the base instead of ports and avoid linker errors. */
+#define LIBICONV_PLUG 1
+#endif
#include <iconv.h>
/* Depending on which standard the iconv() was implemented with,