Fix parallel build race.

gengtype-lex.c is built twice, once for BUILD and once for HOST, but
the BUILD flavour is missing a dependency on $(BCONFIG_H).

2012-11-21  Marcus Shawcroft  <marcus.shawcroft@arm.com>

	* Makefile.in (gengtype-lex.o): Add dependency on $(BCONFIG_H).

From-SVN: r193691