Actually run the installer in build_win.bat.

appveyor.yml

@@ -30,7 +30,7 @@ install:
     - call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat" %platform%
     - build_win test-install
     - set janet_outname=%appveyor_repo_tag_name%
-    - if "%janet_outname%"=="" set janet_outname=v1.8.1
+    - if "%janet_outname%"=="" set /P janet_outname=<build\version.txt
 build: off
 
 artifacts:
@@ -49,8 +49,7 @@ artifacts:
     - name: "janet-$(janet_outname)-windows-%platform%"
       path: dist
       type: Zip
-    - path: "janet-$(janet_outname)-windows-installer.exe"
-      name: "janet-$(janet_outname)-windows-%platform%-installer.exe"
+    - path: "janet-$(janet_outname)-windows-%platform%-installer.exe"
       type: File
 
 deploy:

build_win.bat

@@ -131,7 +131,7 @@ exit /b 0
 @rem Run the installer. (Installs to the local user with default settings)
 :INSTALL
 @echo Running Installer...
-FOR %%a in (janet-*-windows-installer.exe) DO (
+FOR %%a in (janet-*-windows-*-installer.exe) DO (
     %%a /S /CurrentUser
 )
 exit /b 0

janet-installer.nsi

@@ -1,3 +1,6 @@
+# This file is invoked by build_win.bat
+# Relevant configuration variables are set there.
+
 Unicode True
 
 !echo "Program Files: ${PROGRAMFILES}"
@@ -20,6 +23,9 @@ VIFileVersion "${PRODUCT_VERSION}"
 
 !if ${SIXTYFOUR} == "true"
     !define MULTIUSER_USE_PROGRAMFILES64
+    !define PLATNAME "x64"
+!else
+    !define PLATNAME "x86"
 !endif
 
 # Includes
@@ -36,12 +42,12 @@ Name "Janet"
 !define DOLLAR "$"
 !ifdef CHECK_${DOLLAR}%APPVEYOR_REPO_TAG_NAME%
     # We are not in the appveyor environment, use version name
-    !define OUTNAME_PART v${VERSION}
+    !define OUTNAME_PART ${VERSION}
 !else
     # We are in appveyor, use git tag name for installer
     !define OUTNAME_PART ${OUTNAME}
 !endif
-OutFile "janet-${OUTNAME_PART}-windows-installer.exe"
+OutFile "janet-${OUTNAME_PART}-windows-${PLATNAME}-installer.exe"
 
 # Some Configuration
 !define APPNAME "Janet"