diff --git a/runtime/doc/if_mzsch.txt b/runtime/doc/if_mzsch.txt
index 7e206f5..a9a0313 100644
--- a/runtime/doc/if_mzsch.txt
+++ b/runtime/doc/if_mzsch.txt
@@ -1,4 +1,4 @@
-*if_mzsch.txt*  For Vim version 8.0.  Last change: 2016 Jan 24
+*if_mzsch.txt*  For Vim version 8.0.  Last change: 2017 Oct 08
 
 
 		  VIM REFERENCE MANUAL    by Sergey Khorev
@@ -278,12 +278,15 @@
 use Vim without these DLL files.
 NOTE: Newer version of MzScheme (Racket) require earlier (trampolined)
 initialisation via scheme_main_setup.  So Vim always loads the MzScheme DLL at
-startup if possible.
+startup if possible.  This may make Vim startup slower.
 
 To use the MzScheme interface the MzScheme DLLs must be in your search path.
 In a console window type "path" to see what directories are used.
 
-The names of the DLLs must match the MzScheme version Vim was compiled with.
+On MS-Windows the options 'mzschemedll' and 'mzschemegcdll' are used for the
+name of the library to load.  The initial value is specified at build time.
+
+The version of the DLL must match the MzScheme version Vim was compiled with.
 For MzScheme version 209 they will be "libmzsch209_000.dll" and
 "libmzgc209_000.dll". To know for sure look at the output of the ":version"
 command, look for -DDYNAMIC_MZSCH_DLL="something" and
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 56697d5..ebe9c92 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -5468,6 +5468,31 @@
 	time in msec between two mouse clicks for the second click to be
 	recognized as a multi click.
 
+						*'mzschemedll'*
+'mzschemedll'		string	(default depends on the build)
+			global
+			{not in Vi}
+			{only available when compiled with the |+mzscheme/dyn|
+			feature}
+	Specifies the name of the MzScheme shared library. The default is
+	DYNAMIC_MZSCH_DLL which was specified at compile time.
+	Environment variables are expanded |:set_env|.
+	This option cannot be set from a |modeline| or in the |sandbox|, for
+	security reasons.
+
+						*'mzschemegcdll'*
+'mzschemegcdll'		string	(default depends on the build)
+			global
+			{not in Vi}
+			{only available when compiled with the |+mzscheme/dyn|
+			feature}
+	Specifies the name of the MzScheme GC shared library. The default is
+	DYNAMIC_MZGC_DLL which was specified at compile time.
+	The value can be equal to 'mzschemedll' if it includes the GC code.
+	Environment variables are expanded |:set_env|.
+	This option cannot be set from a |modeline| or in the |sandbox|, for
+	security reasons.
+
 						    *'mzquantum'* *'mzq'*
 'mzquantum' 'mzq'	number	(default 100)
 			global