Fix CFLAGS order.
Fix detected flags from ACX_PTHREAD being reset.
Include path should be CPPFLAGS, not CFLAGS.
Fix incorrect variable incrementation in testall.
Redmine#5241: do not reevaluate promises for known classes
Short-circut evaluation of classes promises if class is already set

Close #5241
Acceptance test unstaged
Default bundlesequence to { main }

This removes the need for a body common control to satisfy
a runnable policy. For example a runnable policy may be

bundle agent main {
 reports:
   "hello world";
}

Redmine #4993
Merge pull request #1765 from jimis/minor

Fix detected flags from ACX_PTHREAD being reset.
Redmine#4993: acceptance tests
Revert "Apparently we can't support size_t's z modifier in formats."

This reverts (most of) commit ef3b5fe24263f47db8ef937f450cd3655c1b59b4.

BIG FAT NOTE: We provide a C99 snprintf(). So our Log() function and
              most other libutils facilies *are perfectly good* with C99
              modifiers. You should only avoid C99 modifiers when
              calling non-snprintf functions directly from libc, e.g. an
              fprintf() call.

Conflicts:
	cf-serverd/tls_server.c
	libpromises/dbm_tokyocab.c
	libpromises/eval_context.c
	libpromises/evalfunction.c
	libpromises/policy.c
	libpromises/promises.c
Log() can use C99.
Log() and cfPS() can both use C99.
Log() can use C99.
Some incompliant printf()s segfault ...

... when asked to write to an NULL buffer. From snprint man page:

C99 allows str to be NULL in this case, and gives the return value (as
always) as the number of characters that would have been written in case
the output string has been large enough.
Reflowed HACKING.md with set-fill-column set to 78.
Update HACKING.md to clarify our C99 support status.
Added another test according to @ediosyncratic's review.
Demote MAX_FD Log message from ERR to WARNING, since the array is grown if needed.
Changed message wording to be symmetric with 'accepting connection'.
Changed server's reconfiguration message to NOTICE so that it's always logged in syslog.