patch 8.2.4370: MS-Windows: libsodium.dll not included with the installer

Problem:    MS-Windows: libsodium.dll not included with the installer.
Solution:   Add the file to the installer if it exists. (Christian Brabandt,
            closes #9762)
diff --git a/nsis/gvim.nsi b/nsis/gvim.nsi
index 649c695..c32a886 100644
--- a/nsis/gvim.nsi
+++ b/nsis/gvim.nsi
@@ -348,6 +348,9 @@
 !if /FileExists "${VIMSRC}\vim${BIT}.dll"
 	File ${VIMSRC}\vim${BIT}.dll
 !endif
+!if /FileExists "${VIMRT}\libsodium.dll"
+	File ${VIMRT}\libsodium.dll
+!endif
 	File /oname=install.exe ${VIMSRC}\installw32.exe
 	File /oname=uninstall.exe ${VIMSRC}\uninstallw32.exe
 	File ${VIMSRC}\vimrun.exe
diff --git a/src/version.c b/src/version.c
index 3c67682..b7fbbbd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4370,
+/**/
     4369,
 /**/
     4368,