[libxml2] Fix building with ICU 68.

[Nick Wellnhofer <nwellnhof src gnome org>]

commit b516ed189eb440e909f36baca1557b98e4d9ffd7
Author: Frederik Seiffert <frederik algoriddim com>
Date:   Thu Nov 12 12:53:43 2020 +0100

    Fix building with ICU 68.
    
    ICU 68 no longer defines the TRUE macro.
    
    Closes #204.

 encoding.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/encoding.c b/encoding.c
index c34aca44..264f60bb 100644
--- a/encoding.c
+++ b/encoding.c
@@ -2004,7 +2004,7 @@ xmlEncOutputChunk(xmlCharEncodingHandler *handler, unsigned char *out,
 #ifdef LIBXML_ICU_ENABLED
     else if (handler->uconv_out != NULL) {
         ret = xmlUconvWrapper(handler->uconv_out, 0, out, outlen, in, inlen,
-                              TRUE);
+                              1);
     }
 #endif /* LIBXML_ICU_ENABLED */
     else {