patch 7.4.1976
Problem:    Number variables are not 64 bits while they could be.
Solution:   Add the num64 feature. (Ken Takata)
diff --git a/runtime/doc/various.txt b/runtime/doc/various.txt
index 067ae6e..31f1a1b 100644
--- a/runtime/doc/various.txt
+++ b/runtime/doc/various.txt
@@ -390,6 +390,7 @@
 m  *+mzscheme*		Mzscheme interface |mzscheme|
 m  *+mzscheme/dyn*	Mzscheme interface |mzscheme-dynamic| |/dyn|
 m  *+netbeans_intg*	|netbeans|
+   *+num64*		64-bit Number support |Number|
 m  *+ole*		Win32 GUI only: |ole-interface|
 N  *+packages*		Loading |packages|
 N  *+path_extra*	Up/downwards search in 'path' and 'tags'