No need to autoparse if we have a fwd decl.

(cherry picked from commit 27b97fd6a97ece2393b00f6d866b8d1c07164376)
Do not autoparse the class, but #include headers from libs.

An #include of "TH1F.h" was converted into an autoparse of TH1F (for headers
starting with 'T' and ending on ".h"). This was often doing the right thing; a
better solution (implemented here) would be to #include that header with
autoparsing disabled (which is the crucial part!) to prevent recusrive
autoparsing - but to do that only for those headers that are guaranteed to be
compilable because they "come from a library".

ROOT headers will not be autoparsed (because they are in the PCH), all others
will be autoparsed. For the former, the explicit #include during tryAutoParse()
will prevent recursive autoparsing.

(cherry picked from commit c1a572e966a8cb13286b1425d4ccf49308830bae)
Pass the FileEntry for #inclusions, use that to #include.

Fixes cases where the file is found relative to the include's directory, e.g.
.L /foo/bar/test.C
which has
This header cannot be found with any -I but only relative to the includer.
As we know the full path of the file to be included we will just use that.

Fixes out-of-source roottest/root/meta/autoloading/execAutoloadOnInclusion.C

(cherry picked from commit 84ff4fc8b38396e75b3e4b20646d33cc8945260d)