First attempt at appveyor configuration

appveyor.yml

@@ -0,0 +1,12 @@
+version: 1.0.{build}
+
+image: Visual Studio 2017
+
+build:
+  verbosity: minimal
+
+init:
+  - call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"
+
+build_script:
+  - scripts_windows\build_all.bat

scripts_windows/build_all.bat

@@ -0,0 +1,19 @@
+@ECHO OFF
+SETLOCAL
+SET EL=0
+
+REM CALL "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"
+REM IF ERRORLEVEL 1 SET EL=1
+
+FOR /D %%K IN (crypto_kem\*) DO (
+  FOR /D %%L IN (%%K\*) DO (
+    cd %%L
+    nmake /f Makefile.Microsoft_nmake clean
+    IF ERRORLEVEL 1 SET EL=2
+    nmake /f Makefile.Microsoft_nmake
+    IF ERRORLEVEL 1 SET EL=3
+    cd ..\..\..
+  )
+)
+
+EXIT /b %EL%