gitlab-ci: Add a mingw x86_64 job

Acked-by: Eric Engestrom <eric.engestrom@intel.com> (v1)
Acked-by: Kristian H. Kristensen <hoegsberg@google.com>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f245ee6..b5d2d2f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -14,7 +14,7 @@
 # repository's registry will be used there as well.
 variables:
   UPSTREAM_REPO: mesa/mesa
-  DEBIAN_TAG: "2019-09-30"
+  DEBIAN_TAG: "2019-10-07_1"
   DEBIAN_ARM64_TAG: "arm64v8-2019-08-09"
   STRETCH_TAG: "2019-09-18"
   DEBIAN_VERSION: buster-slim
@@ -344,6 +344,17 @@
       -D llvm=false
       -D osmesa=classic
 
+meson-mingw32-x86_64:
+  extends: .meson-build
+  variables:
+    UNWIND: "false"
+    DRI_DRIVERS: ""
+    GALLIUM_DRIVERS: "swrast"
+    EXTRA_OPTION: >
+      -Dllvm=false
+      -Dosmesa=gallium
+      --cross-file=.gitlab-ci/x86_64-w64-mingw32
+
 scons:
   extends: .scons-build
   variables: