bug#25479: memory leaks in dfa

[Arnold Robbins]

Hi Grep Guys.

Please:

        clone gawk repo
        cd gawk
        ./bootstrap.sh && ./configure && make -j
        make valgrind

Look at the 'definitely lost' lines.  For example:

==30472== 240 bytes in 2 blocks are definitely lost in loss record 128 of 170
==30472==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64
-linux.so)
==30472==    by 0x44D42A: emalloc_real (awk.h:1923)
==30472==    by 0x44D42A: xmalloc (gawkmisc.c:57)
==30472==    by 0x468806: xnmalloc (xalloc.h:134)
==30472==    by 0x468806: alloc_position_set (dfa.c:2057)
==30472==    by 0x468D93: epsclosure (dfa.c:2272)
==30472==    by 0x468D93: dfaanalyze (dfa.c:2601)
==30472==    by 0x46CA84: dfacomp (dfa.c:3531)
==30472==    by 0x463284: make_regexp (re.c:231)
==30472==    by 0x414548: make_regnode (awkgram.y:5005)
==30472==    by 0x416A33: yyparse (awkgram.y:505)
==30472==    by 0x41C9E3: parse_program (awkgram.y:2580)
==30472==    by 0x40D373: main (main.c:459)

There may be other paths as well.

Can y'all track this down and fix?

Thanks,

Arnold