Allow further configuration of error patterns

Dockerfile

@@ -51,13 +51,16 @@ RUN \
     || true && \
     # Handle console output of MDK537 installer
     handle_output() { \
+        # A pattern that is supposed to indicates that wine got stuck
         pattern="fixme:win:NtUserLockWindowUpdate ((nil))"; \
+        # The amount of times the pattern should occur for the process to be considered stuck
+        patternCount=2; \
         output=$( \
             sed \
                 # Handle exit hints
                 -e "s/^exit \([[:digit:]]\+\)$/\1/; t end;" \
                 # Handle multiple occurrences of $pattern
-                -e "/$pattern/{ x; s/^x\{1\}$/\0/; t stuck; s/^\(x*\)$/\1x/; x; };" \
+                -e "/$pattern/{ x; s/^x\{$(expr $patternCount - 1)\}$/\0/; t stuck; s/^\(x*\)$/\1x/; x; };" \
                 # Delete output and return to start
                 -e "d; b;" \
                 # Branch "stuck": delete output and exit with code 42