variables: use parse.assert' instead of debug'.

* src/getargs.c (getargs): Map -t to %define trace.parse.
	* src/scan-gram.l (%debug): Map to %define trace.parse.
	* data/bison.m4 (b4_percent_define_if_define): Map `.' in variable
	names to `_' in macro names.
	(b4_debug_if): Replace with...
	(b4_parse_trace_if): this.
	* data/glr.c, data/glr.cc, data/lalr1.cc, data/lalr1.java,
	* data/yacc.c: Adjust.
	* doc/bison.texinfo (Decl Summary): Document %debug as obsoleted.
	Use @code to label the variable list.
	Document the variable parse.trace.
	(Tracing): Promote the parse.trace variable.
	* TODO: %printer is not documented.

TODO

@@ -15,8 +15,6 @@ I have seen messages like the following from GCC.
 <built-in>:0: fatal error: opening dependency file .deps/libltdl/argz.Tpo: No such file or directory
 
 
-** Document %define assert
-
 ** Discuss about %printer/%destroy in the case of C++.
 It would be very nice to provide the symbol classes with an operator<<
 and a destructor.  Unfortunately the syntax we have chosen for
@@ -292,7 +290,10 @@ this issue.  Does anybody have it?
 Some history of Bison and some bibliography would be most welcome.
 Are there any Texinfo standards for bibliography?
 
+** %printer
+Wow, %printer is not documented.  Clearly mark YYPRINT as obsolete.
 
+** %define assert
 
 * Java, Fortran, etc.