Use branch cpp17 as default.

appveyor/install_kiwix-desktop.cmd

@@ -2,6 +2,7 @@ REM ========================================================
 REM Install kiwix-desktop
 git clone https://github.com/kiwix/kiwix-desktop || exit /b 1
 cd kiwix-desktop
+git checkout cpp17 || exit /b 1
 echo "Running qmake"
 SET _WITH_CONSOLE=1
 IF %KIWIX_DESKTOP_RELEASE% EQU 1 (

appveyor/install_libkiwix.cmd

@@ -2,6 +2,7 @@ REM ========================================================
 REM Install libkiwix
 git clone https://github.com/kiwix/libkiwix.git || exit /b 1
 cd libkiwix
+git checkout cpp17 || exit /b 1
 set CPPFLAGS="-I%EXTRA_DIR%/include"
 meson . build --prefix %EXTRA_DIR% --default-library static --buildtype release || exit /b 1
 cd build

appveyor/install_libzim.cmd

@@ -2,6 +2,7 @@ REM ========================================================
 REM Install libzim
 git clone https://github.com/openzim/libzim.git || exit /b 1
 cd libzim
+git checkout cpp17 || exit /b 1
 meson . build --prefix %EXTRA_DIR% --default-library static --buildtype release || exit /b 1
 cd build
 ninja || exit /b 1

kiwixbuild/dependencies/base.py

@@ -137,7 +137,7 @@ class ReleaseDownload(Source):
 
 
 class GitClone(Source):
-    base_git_ref = "main"
+    base_git_ref = "cpp17"
     force_full_clone = False
 
     @property