Made use of Travis CI's Windows support.

At least for now there seems to be no point in trying to build the libraries (and run the tests) on Windows. Rather we only want to check that the MSVC solution is still valid.

.travis.yml

@@ -1,16 +1,24 @@
-language:
-  - c
-install:
-  - sudo apt-get update
-  - sudo apt-get install linuxdoc-tools linuxdoc-tools-info binutils-mingw-w64-i686 gcc-mingw-w64-i686 sshpass
-script:
-  - make bin USER_CFLAGS=-Werror
-  - make lib QUIET=1
-  - make test QUIET=1
-  - make samples
-  - make -C src clean
-  - make bin USER_CFLAGS=-Werror CROSS_COMPILE=i686-w64-mingw32-
-  - make -C samples clean
-  - make doc zip
-after_success:
-  - make -f Makefile.travis
+language: c
+
+jobs:
+  include:
+
+  - os: linux
+    install:
+      - sudo apt-get update
+      - sudo apt-get install linuxdoc-tools linuxdoc-tools-info binutils-mingw-w64-i686 gcc-mingw-w64-i686 sshpass
+    script:
+      - make bin USER_CFLAGS=-Werror
+      - make lib QUIET=1
+      - make test QUIET=1
+      - make samples
+      - make -C src clean
+      - make bin USER_CFLAGS=-Werror CROSS_COMPILE=i686-w64-mingw32-
+      - make -C samples clean
+      - make doc zip
+    after_success:
+      - make -f Makefile.travis
+
+  - os: windows
+    script:
+      - MSBuild.exe scr/cc65.sln