re-starting xvfb-run too fast makes problems. Trying with -a
--- a/windows_installer.mk Sat Aug 13 18:17:10 2022 +0200
+++ b/windows_installer.mk Sat Aug 13 23:18:01 2022 +0200
@@ -14,7 +14,7 @@
msysdir=msys32
MSYS_ROOT=$(CURDIR)/$(msysdir)
-XVFBRUN ?= xvfb-run
+XVFBRUN ?= xvfb-run -a
mingw32dir=$(msysdir)/mingw32
mingw32finaldir=installer/mingw32