segfault (memory leak?) in GNU Make 3.82.90 (CVS HEAD)

[Martin d'Anjou]

Hi,

I am getting a segmentation fault with GNU Make 3.82.90 (CVS HEAD as of 
earlier today). To obtain more information, I have run it in valgrind. 
The report is quite long, here is an excerpt:

...
==6816== Invalid write of size 8
==6816==    at 0x40B428: pattern_search (implicit.c:688)
==6816==    by 0x40BA3E: pattern_search (implicit.c:755)
==6816==    by 0x40BA3E: pattern_search (implicit.c:755)
==6816==    by 0x40C1A0: try_implicit_rule (implicit.c:45)
==6816==    by 0x418FB5: update_file (remake.c:491)
==6816==    by 0x419C15: update_goal_chain (remake.c:155)
==6816==    by 0x411C25: main (main.c:2337)
==6816==  Address 0x5405530 is 0 bytes after a block of size 64 alloc'd
==6816==    at 0x4A0776F: malloc (vg_replace_malloc.c:263)
==6816==    by 0x4125A8: xmalloc (misc.c:374)
==6816==    by 0x40ABB2: pattern_search (implicit.c:221)
==6816==    by 0x40BA3E: pattern_search (implicit.c:755)
==6816==    by 0x40BA3E: pattern_search (implicit.c:755)
==6816==    by 0x40C1A0: try_implicit_rule (implicit.c:45)
==6816==    by 0x418FB5: update_file (remake.c:491)
==6816==    by 0x419C15: update_goal_chain (remake.c:155)
==6816==    by 0x411C25: main (main.c:2337)
...
==6816== Process terminating with default action of signal 11 (SIGSEGV)
==6816==  Access not within mapped region at address 0x0
==6816==    at 0x4A08862: strlen (mc_replace_strmem.c:390)
==6816==    by 0x41B428: strcache_add (strcache.c:191)
==6816==    by 0x40BC08: pattern_search (implicit.c:883)
==6816==    by 0x40BA3E: pattern_search (implicit.c:755)
==6816==    by 0x40BA3E: pattern_search (implicit.c:755)
==6816==    by 0x40C1A0: try_implicit_rule (implicit.c:45)
==6816==    by 0x418FB5: update_file (remake.c:491)
==6816==    by 0x419C15: update_goal_chain (remake.c:155)
==6816==    by 0x411C25: main (main.c:2337)
...
==6816== LEAK SUMMARY:
==6816==    definitely lost: 85 bytes in 4 blocks
==6816==    indirectly lost: 0 bytes in 0 blocks
==6816==      possibly lost: 3 bytes in 1 blocks
==6816==    still reachable: 672,520 bytes in 3,700 blocks
==6816==         suppressed: 0 bytes in 0 blocks
...

I don't know how to narrow my makefile down to find the culprit.

Thanks in advance,
Martin