Intermittent t/60macro.t failure

[Gavin Smith]

Tested with git commit 0fb51499dd.

TEXINFO_XS=require perl -w t/60macro.t

often produces a test failure in the 'macro_in_def_delimiters' test.
It does not happen every time so I suspect a memory error.

TEXINFO_XS=require perl -w t/60macro.t macro_in_def_delimiters

on its own seems to be ok so it may be an earlier test that caused the
problem.

It seems to be related to sourcemarks:

$ diff t/results/macro/macro_in_def_delimiters.pl*
414,421d413
<                       'source_marks' => [
<                         {
<                           'counter' => 4,
<                           'position' => 1,
<                           'sourcemark_type' => 'macro_expansion',
<                           'status' => 'end'
<                         }
<                       ],

I ran

alias VAL='valgrind --log-file=val.log'
TEXINFO_XS=require VAL perl -w t/60macro.t macro_in_misc_commands

and in val.log there is:

==226968== Conditional jump or move depends on uninitialised value(s)
==226968==    at 0x82DCAC8: relocate_source_marks (source_marks.c:208)
==226968==    by 0x82BA281: isolate_last_space_internal (parser.c:829)
==226968==    by 0x82BA591: isolate_last_space (parser.c:921)
==226968==    by 0x82CBEA1: end_line_misc_line (end_line.c:1357)
==226968==    by 0x82CEAEC: end_line (end_line.c:2304)
==226968==    by 0x82BFCA5: process_remaining_on_line (parser.c:2218)
==226968==    by 0x82C052D: parse_texi (parser.c:2348)
==226968==    by 0x82B1BB9: parse_piece (api.c:246)
==226968==    by 0x82AF2D1: XS_Texinfo__Parser_parse_piece (Parsetexi.c:241)
==226968==    by 0x2119D7: Perl_pp_entersub (in /usr/bin/perl)
==226968==    by 0x208135: Perl_runops_standard (in /usr/bin/perl)
==226968==    by 0x17B8DB: perl_run (in /usr/bin/perl)

I haven't investigated further but it's likely that fixing these
valgrind errors would stop the test failures.