Instead of specifying AST_MODFLAG_LOAD_ORDER with load_pri
AST_MODPRI_DEFAULT just use AST_MODFLAG_DEFAULT.

Change-Id: I0123258eafce324249433a69df15a85cc16e509f

ASTERISK_REGISTER_FILE no longer has any purpose so this commit removes
all traces of it.

Previously exported symbols removed:
* __ast_register_file
* __ast_unregister_file
* ast_complete_source_filename

This also removes the mtx_prof static variable that was declared when
MTX_PROFILE was enabled.  This variable was only used in lock.c so it
is now initialized in that file only.

ASTERISK-26480 #close

Change-Id: I1074af07d71f9e159c48ef36631aa432c86f9966

The retrieve_cache_control_directives test has been failing occasionally
in Jenkins. The apparent failure occurs when attempting to validate the
expiration of the retrieved file.

After reproducing, the problem was pretty clear. At the beginning of the
test, the current time is retrieved. The seconds value of this timestamp
is X. When the file is retrieved, res_http_media_cache calculates the
expiration and in doing so retrieves the current time. In most cases,
since the test executes quickly, it will also retrieve a timestamp with
X seconds. However, if the test starts very near to when the timestamp
seconds are set to increment, res_http_media_cache may retrieve a
timestamp with X+1 seconds instead.

The test attempted to account for this by allowing a tolerance of 1
second when validating the expiration. However, the problem was that the
comparisons being used in the validation used > and < operations. This
meant that values that fell within the tolerance (because they equaled
the upper bound of the tolerance) would fail.

The solution is to use >= and <= operators in the expiration validation.

However, I estimated that while the one second tolerance should be
fine on most machines, it would still be possible on a very slow machine
to end up falling outside the one second tolerance. So I have also
relaxed the tolerance of expiration validation to be three seconds
instead.

The final change here is to add a debug message when validating
expiration so that we can see what values are being compared.

ASTERISK-25959 #close
Reported by Joshua Colp

Change-Id: Ic1a0e10722c1c5d276d5a4d6a67136d6ec26c247

Change-Id: Ie8a9ae3d13bdeaacafc8d28271adc6707f633a5f

This patch adds unit tests for res_http_media cache, that covers nominal
creation and retrieval - and through them as well, staleness and deletion
checks. In addition, this patch adds tests that covers the interaction of
various HTTP headers, including Expires, Etag, and Cache-Control.

ASTERISK-25654

Change-Id: I2db101e307c863857fe416d6f5bf4cace9ac7cf5