test building on multiple MacOS versions

.travis.yml

@@ -110,13 +110,45 @@ matrix:
         - PLATFORM=x86_64
         - VMTYPE=test
     - os: osx
-      name: "MacOS 64-bit"
+      name: "MacOS 10.10"
+      language: generic
+      osx_image: xcode6.4
+      env:
+        - GAMOS=macos
+        - PLATFORM=x86_64
+        - VMTYPE=build
+    - os: osx
+      name: "MacOS 10.11"
+      language: generic
+      osx_image: xcode8
+      env:
+        - GAMOS=macos
+        - PLATFORM=x86_64
+        - VMTYPE=build
+    - os: osx
+      name: "MacOS 10.12"
       language: generic
       osx_image: xcode9.2
       env:
         - GAMOS=macos
         - PLATFORM=x86_64
         - VMTYPE=build
+    - os: osx
+      name: "MacOS 10.13"
+      language: generic
+      osx_image: xcode10.1
+      env:
+        - GAMOS=macos
+        - PLATFORM=x86_64
+        - VMTYPE=build
+    - os: osx
+      name: "MacOS 10.14"
+      language: generic
+      osx_image: xcode11
+      env:
+        - GAMOS=macos
+        - PLATFORM=x86_64
+        - VMTYPE=build
     - os: windows
       name: "Windows 64-bit"
       language: shell

src/travis/osx-x86_64-install.sh

@@ -7,6 +7,7 @@ export GAMVERSION=`gam/gam version simple`
 cp LICENSE gam
 cp whatsnew.txt gam
 cp GamCommands.txt gam
-GAM_ARCHIVE=gam-$GAMVERSION-$GAMOS-$PLATFORM.tar.xz
+MACOSVERSION=$(defaults read loginwindow SystemVersionStampAsString)
+GAM_ARCHIVE=gam-$GAMVERSION-$GAMOS-$PLATFORM-MacOS$MACOSVERSION.tar.xz
 rm gam/lastupdatecheck.txt
 tar cfJ $GAM_ARCHIVE gam/