patch 9.1.1499: MS-Windows: no indication of ARM64 architecture

Problem:  MS-Windows: no indication of ARM64 architecture
Solution: Add ARM64 to version output and include in nsis installer
          (RestorerZ)

related: vim/vim-win32-installer#381
closes: #17642

Signed-off-by: RestorerZ <restorer@mail2k.ru>
Signed-off-by: Christian Brabandt <cb@256bit.org>

nsis/gvim.nsi

@@ -53,6 +53,18 @@ Unicode true
   !define WIN64 0
 !endif
 
+# if you want to create the installer for ARM64, use the /DARM64=1 on
+# the command line makensis.exe. This property will be set to 1.
+!ifndef ARM64
+  !define ARM64 0
+!else
+  !if ${ARM64} > 0
+    !if ${WIN64} < 1
+      !define /redef WIN64 1
+    !endif
+  !endif
+!endif
+
 # if you don't want to include libgcc_s_sjlj-1.dll in the package, use the
 # switch /DINCLUDE_LIBGCC=0 on the command line makensis.exe.
 !ifndef INCLUDE_LIBGCC
@@ -113,9 +125,13 @@ ${StrRep}
 !define UNINST_REG_KEY_VIM  "${UNINST_REG_KEY}\${PRODUCT}"
 
 !if ${WIN64}
-Name "${PRODUCT} (x64)"
+  !if ${ARM64}
+    Name "${PRODUCT} (ARM64)"
+  !else
+    Name "${PRODUCT} (x64)"
+  !endif
 !else
-Name "${PRODUCT}"
+  Name "${PRODUCT}"
 !endif
 OutFile gvim${VER_MAJOR}${VER_MINOR}.exe
 CRCCheck force