Update .appveyor.yml.

- Set options to be the same as travis builds,
  except use warnings=all instead of warnings=extra.
- Fail on warnings as per travis builds.

(cherry picked from commit 106221a733)

Edited to set `werror=no` until we've fixed all warnings.

.appveyor.yml

@@ -7,10 +7,15 @@ environment:
   PYTHON: C:\Python38
   SCONS_CACHE_ROOT: "%HOME%\\scons_cache"
   SCONS_CACHE_LIMIT: 1024
+  OPTIONS: "debug_symbols=no verbose=yes progress=no"
+  EXTRA_ARGS: "warnings=all werror=no"
   matrix:
-    - GD_PLATFORM: windows
-      TOOLS: yes
-      TARGET: release_debug
+  - GD_PLATFORM: windows
+    TARGET: release_debug
+    TOOLS: yes
+
+matrix:
+  fast_finish: true
 
 init:
   - ps: if ($env:APPVEYOR_REPO_BRANCH -ne "3.2") { $env:APPVEYOR_CACHE_SKIP_SAVE = "true" }
@@ -31,7 +36,7 @@ before_build:
   - set "SCONS_CACHE=%SCONS_CACHE_ROOT%\%APPVEYOR_REPO_BRANCH%"
 
 build_script:
-  - scons platform=%GD_PLATFORM% target=%TARGET% tools=%TOOLS% debug_symbols=no verbose=yes progress=no gdnative_wrapper=yes
+  - scons platform=%GD_PLATFORM% target=%TARGET% tools=%TOOLS% %OPTIONS% %EXTRA_ARGS%
 
 after_build:
   - git rev-parse --short=9 HEAD > VERSION_HASH.txt