patch 7.4.1106
Problem:    The nsis script can't be used from the appveyor build.
Solution:   Add "ifndef" to allow for variables to be set from the command
            line. Remove duplicate SetCompressor command. Support using other
            gettext binaries. (Ken Takata)  Update build instructions to use
            libintl-8.dll.
diff --git a/src/main.c b/src/main.c
index d7723d2..175bbde 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1580,7 +1580,7 @@
 
 #  ifdef DYNAMIC_GETTEXT
 	/* Initialize the gettext library */
-	dyn_libintl_init(NULL);
+	dyn_libintl_init();
 #  endif
 	/* expand_env() doesn't work yet, because chartab[] is not initialized
 	 * yet, call vim_getenv() directly */