diagnostic.c (diagnostic_build_prefix): Always print columns.

gcc/
	* diagnostic.c (diagnostic_build_prefix): Always print columns.
	(diagnostic_report_current_module): Print columns.
	* common.opt (flag_show_column): Enable by default.
gcc/testsuite/
	* lib/gcc-dg.exp (dg-bogus): Override dg-bogus.
	(process-message): Expect column numbers.
	* gcc.dg/va-arg-2.c: Use line 0 to indicate no column.
	* gcc.dg/pch/counter-2.c: Same.
	* gcc.dg/pch/valid-2.c: Same.
	* gcc.dg/pch/warn-1.c: Same.
	* gcc.dg/pch/valid-1.c: Same.
	* gcc.dg/cpp/include2a.c: Handle lack of columns.
	* gcc.dg/cpp/syshdr.c: Same.
	* gcc.dg/cpp/19940712-1.c: Same.
	* gcc.dg/cpp/missing-header-1.c: Same.
	* gcc.dg/cpp/unc4.c: Remove -fno-show-column.
	* gcc.dg/cpp/tr-warn3.c: Same.
	* gcc.dg/cpp/pr29612-2.c: Same.
	* gcc.dg/cpp/tr-warn4.c: Same.
	* gcc.dg/cpp/Wtrigraphs.c: Same.
	* gcc.dg/cpp/poison.c: Same.
	* gcc.dg/cpp/arith-3.c: Same.
	* gcc.dg/cpp/sysmac2.c: Same.
	* gcc.dg/cpp/cpp.exp: Same.
	* gcc.dg/cpp/tr-warn5.c: Same.
	* gcc.dg/cpp/include2.c: Same.
	* gcc.dg/cpp/Wmissingdirs.c: Same.
	* gcc.dg/cpp/Wmissingdirs.c: Same.
	* gcc.dg/cpp/tr-warn6.c: Same.
	* gcc.dg/cpp/Wtrigraphs-2.c: Same.
	* gcc.dg/cpp/macspace1.c: Same.
	* gcc.dg/cpp/escape-2.c: Same.
	* gcc.dg/cpp/assert2.c: Same.
	* gcc.dg/cpp/undef2.c: Same.
	* gcc.dg/cpp/macspace2.c: Same.
	* gcc.dg/cpp/tr-warn1.c: Same.
	* gcc.dg/cpp/extratokens2.c: Same.
	* gcc.dg/cpp/strify2.c: Same.
	* gcc.dg/cpp/Wsignprom.c: Same.
	* gcc.dg/cpp/redef2.c: Same.
	* gcc.dg/cpp/trad/trad.exp: Same.
	* gcc.dg/cpp/arith-1.c: Same.
	* gcc.dg/cpp/extratokens.c: Same.
	* gcc.dg/cpp/if-mpar.c: Same.
gcc/cp/
	* error.c (print_instantiation_partial_context): Print column
	numbers.
libcpp/
	* include/line-map.h (LAST_SOURCE_COLUMN): New.

From-SVN: r148052