Compile kiwix-tools for windows with a recent mingw.

.travis.yml

@@ -70,6 +70,7 @@ script:
   then
     VARIANT=xenial
     if [[ $DESKTOP_ONLY = 1 ]]; then VARIANT=bionic; fi
+    if [[ $PLATFORM =~ ^win32_* ]]; then VARIANT=bionic; fi
   fi
 - |
   if [[ $TRAVIS_OS_NAME = "linux" ]]
@@ -106,7 +107,7 @@ env:
   global:
     - NIGHTLY_DATE=$(date +%Y-%m-%d)
     - SSH_KEY=/tmp/private/travisci_builder_id_key
-    - DOCKER_VERSION=1
+    - DOCKER_VERSION=2
   matrix:
     - PLATFORM="flatpak" DESKTOP_ONLY=1
     - PLATFORM="native_dyn"

travis/bionic_builder.dockerfile

@@ -17,6 +17,8 @@ RUN apt update -q && \
     libfuse2 fuse patchelf \
 # Flatpak tools
     elfutils flatpak flatpak-builder \
+# Cross win32 compiler
+    g++-mingw-w64-i686 gcc-mingw-w64-i686 gcc-mingw-w64-base mingw-w64-tools \
 # Other tools (to remove)
 #    vim less grep \
   && \

travis/xenial_builder.dockerfile

@@ -14,8 +14,6 @@ RUN apt update -q && \
 # Packaged dependencies
     libbz2-dev libmagic-dev uuid-dev zlib1g-dev default-jdk \
     libmicrohttpd-dev \
-# Cross win32 compiler
-    g++-mingw-w64-i686 gcc-mingw-w64-i686 gcc-mingw-w64-base mingw-w64-tools \
 # Cross compile i586
     libc6-dev-i386 lib32stdc++6 gcc-multilib g++-multilib \
 # Other tools (to remove)