Add a note on APR/APR-util caching. [skip ci]
@@ -44,6 +44,8 @@ The Travis scripts use the following environment variables:
* TEST_ARGS - arguments to pass to ./t/TEST in the Perl test framework
+* CLEAR_CACHE - if set, the cached $HOME/root is removed before each build
+
Caching
-------
@@ -53,6 +55,15 @@ Anything installed into the $HOME/root directory is cached - notably,
versions of APR/APR-util are installed here and cached across httpd
build jobs without needing to be rebuilt every time.
+The cached installs of APR/APR-util are refreshed if the
+last-changed-revision of the build is stale.
+
+If APR_VERSION and APU_VERSION are both set to 1.x versions, then
+CLEAR_CACHE should also be set to disable APR* caching. APR-util can
+only be rebuilt if an APR checkout is present, so a APR-util cannot be
+built from source alone. (i.e. the scripts do not handle the case of
+cached, fresh APR plus a cached but stale APR-util)
+
TODO list
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