* cygmalloc.h: Make more concessions to attempts to get debugging malloc
working.
* debug.h: Ditto.
* dlmalloc.cc: Ditto.
* dlmalloc.h: Ditto.
* malloc_wrapper.cc: Ditto.
* perthread.h (perthread::create): Use calloc to ensure zeroed memory.
* configure.in: Fill in MALLOC_OFILES with either debugging or regular malloc.
* configure: Regenerate.
* dlmalloc.c: Make various fruitless changes to attempt to get to work.
* dlmalloc.h: Ditto.
* malloc.cc (free): Check malloc pool when debugging.
* path.cc (win32_device_name): Eliminate compiler warning.
* sigproc.cc (sig_dispatch_pending): Remove use of was_pending. Let
thisframe.call_signal_handler decide if handler should be called rather than
using bogus was_pending check.
* exceptions.cc (interrupt_setup): Remove accidentally checked in debugging
code.
* heap.cc (sbrk): Save rounded addess in user_heap_max.
