xgc: update to 1.0.6.

Alan Coopersmith (9):
      Update README for gitlab migration
      Update configure.ac bug URL for gitlab migration
      Fix spelling/wording issues
      Trim trailing whitespace from lines
      gitlab CI: add a basic build test
      Build xz tarballs instead of bzip2
      Use _CONST_X_STRING to make libXt declare String as const char *
      Fix -Wformat-truncation warning
      xgc 1.0.6

Emil Velikov (1):
      autogen.sh: use quoted string variables

Mihail Konev (1):
      autogen: add default patch prefix

Peter Hutterer (1):
      autogen.sh: use exec instead of waiting for configure to finish

(wiz)