improvements in error reporting

[Doug Evans <dje at sebabeach dot org>]

Hi.

fyi, I checked this in.
It's a step in improving error messages.
[plus some minor cleanup]
More to follow ....

2009-08-05  Doug Evans  <dje@sebabeach.org>

	Track source location better, for better error messages.
	* pmacros.scm (-pmacro-eval): Delete, unused.
	(pmacro-expand, -pmacro-expand): New arg `loc', all callers updated.
	(-pmacro-expand-expr-list, -smacro-apply): Ditto.
	(scan-list, scan): Ditto.
	(-pmacro-builtin-pmacro, -pmacro-builtin-let, -pmacro-builtin-if,
	-pmacro-builtin-case, -pmacro-builtin-cond, -pmacro-builtin-begin,
	-pmacro-builtin-andif, -pmacro-builtin-orif): Ditto.
	(scan-list1): New function.
	(-pmacro-build-lambda): New arg `loc', all callers updated.  Rewrite.
	* read.scm (<reader>): New member `location'.
	(-reader-lookup-command): Renamed from reader-lookup-command,
	all callers updated.
	(reader-error): Rewrite to produce better source location info.
	(current-reader-location): New function.
	(-reader-process-expanded-1!): Renamed from -reader-process-expanded-1.
	All callers updated.  Record source location of expression.
	(reader-process-expanded!): Renamed from reader-process-expanded.
	All callers updated.
	(-reader-process!): Renamed from reader-process.  New arg `loc'.
	All callers updated.  Record source location of define-pmacro.
	* utils-cgen.scm (<location>): New class.
	(single-location): New (pseudo) class.
	(pretty-print-single-location, pretty-print-location): New functions.
	(location-top, location-push-single, location-push): New functions.
	(unspecified-location, current-input-location): New functions.
	(location-property): New object property.
	(location-property-set!): New function.
	(<source-ident>): Renamed from <ordered-ident>.  New member `location'.
	All uses updated.
	* testsuite/location-1.test: New testcase.
	* testsuite/run-tests.sh: Fix fail count handling.
	* testsuite/test-utils.sh.in (run_cgen): New option `-f'.  Allow tests
	to expect cgen to fail.

	* pmacros.scm (*): Use "pmacro" instead of "macro" more consistently.

	* read.scm (-cmd-include): Renamed from include.  All callers updated.
	(-cmd-if): Renamed from cmd-if.  All callers updated.
	Use reader-process-expanded! on then/else clauses instead of eval1.