patch 8.2.0667: cannot install Haiku version from source

Problem:    Cannot install Haiku version from source.
Solution:   Update Makefile and rdef file. (Emir Sari, closes #6013)
diff --git a/READMEdir/README_haiku.txt b/READMEdir/README_haiku.txt
index 7eeb0bb..860b40b 100644
--- a/READMEdir/README_haiku.txt
+++ b/READMEdir/README_haiku.txt
@@ -10,4 +10,4 @@
 - Open a Terminal and type "pkgman install vim", then follow instructions.
 
 If you prefer to install Vim from source, follow the instructions on
-"runtime/doc/os_haiku.txt", "Compiling Haiku" section.
+"runtime/doc/os_haiku.txt", "Compiling Vim" section.