sphinx: add links to terms in the BitBake glossary

Using the intersphinx extension, we can refer to terms in the Bitbake
manual using :term:`bitbake:FOO`. This patch implements that, mostly
using the following regexp:

  line = re.sub("`+(\w+)`* <(\&YOCTO_DOCS_BB_URL;)?#var(-bb)?-\\1>`__",
                ":term:`bitbake:\\1`",
                line)

And a handful of manual fixup.

(From yocto-docs rev: d2ed9117fffceb756c4a8f3cb6d39363a271d6d9)

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/dev-manual/dev-manual-common-tasks.rst

@@ -4153,7 +4153,7 @@ directory:
    variable, inherit the
    :ref:`own-mirrors <ref-classes-own-mirrors>`
    class, and use the
-   ```BB_NO_NETWORK`` <&YOCTO_DOCS_BB_URL;#var-bb-BB_NO_NETWORK>`__
+   :term:`bitbake:BB_NO_NETWORK`
    variable to your ``local.conf``. SOURCE_MIRROR_URL ?=
    "file:///home/your-download-dir/" INHERIT += "own-mirrors"
    BB_NO_NETWORK = "1" The ``SOURCE_MIRROR_URL`` and ``own-mirror``
@@ -4215,7 +4215,7 @@ variable for more information:
 -  :term:`BB_NUMBER_THREADS`:
    The maximum number of threads BitBake simultaneously executes.
 
--  ```BB_NUMBER_PARSE_THREADS``: <&YOCTO_DOCS_BB_URL;#var-BB_NUMBER_PARSE_THREADS>`__
+-  :term:`bitbake:BB_NUMBER_PARSE_THREADS`:
    The number of threads BitBake uses during parsing.
 
 -  :term:`PARALLEL_MAKE`: Extra
@@ -8456,7 +8456,7 @@ BitBake has determined by doing the following:
 
    The output of ``bitbake-dumpsig`` also includes the value each
    variable had, a list of dependencies for each variable, and
-   ```BB_HASHBASE_WHITELIST`` <&YOCTO_DOCS_BB_URL;#var-BB_HASHBASE_WHITELIST>`__
+   :term:`bitbake:BB_HASHBASE_WHITELIST`
    information.
 
 There is also a ``bitbake-diffsigs`` command for comparing two

documentation/overview-manual/overview-manual-concepts.rst

@@ -1288,10 +1288,10 @@ dependencies, such as the compiler, from the cache.
 
 The availability of objects in the sstate cache is handled by the
 function specified by the
-```BB_HASHCHECK_FUNCTION`` <&YOCTO_DOCS_BB_URL;#var-BB_HASHCHECK_FUNCTION>`__
+:term:`bitbake:BB_HASHCHECK_FUNCTION`
 variable and returns a list of available objects. The function specified
 by the
-```BB_SETSCENE_DEPVALID`` <&YOCTO_DOCS_BB_URL;#var-BB_SETSCENE_DEPVALID>`__
+:term:`bitbake:BB_SETSCENE_DEPVALID`
 variable is the function that determines whether a given dependency
 needs to be followed, and whether for any given relationship the
 function needs to be passed. The function returns a True or False value.
@@ -2171,7 +2171,7 @@ accomplished using fakeroot.
                       
 
 For more information, see the
-```FAKEROOT*`` <&YOCTO_DOCS_BB_URL;#var-FAKEROOT>`__ variables in the
+:term:`FAKEROOT* <bitbake:FAKEROOT>` variables in the
 BitBake User Manual. You can also reference the "`Why Not
 Fakeroot? <https://github.com/wrpseudo/pseudo/wiki/WhyNotFakeroot>`__"
 article for background information on Fakeroot and Pseudo.

documentation/ref-manual/migration.rst

@@ -4677,7 +4677,7 @@ The following BitBake changes have occurred.
    ``bb.build.exec_func()`` in custom classes or scripts.
 
 -  The
-   ```BB_SETSCENE_VERIFY_FUNCTION2`` <&YOCTO_DOCS_BB_URL;#var-bb-BB_SETSCENE_VERIFY_FUNCTION2>`__
+   :term:`bitbake:BB_SETSCENE_VERIFY_FUNCTION2`
    is no longer used. In the unlikely event that you have any references
    to it, they should be removed.
 
@@ -4687,7 +4687,7 @@ The following BitBake changes have occurred.
    scripts that handles these two events need to be updated.
 
 -  The arguments passed to functions used with
-   ```BB_HASHCHECK_FUNCTION`` <&YOCTO_DOCS_BB_URL;#var-bb-BB_HASHCHECK_FUNCTION>`__
+   :term:`bitbake:BB_HASHCHECK_FUNCTION`
    have changed. If you are using your own custom hash check function,
    see
    http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=40a5e193c4ba45c928fccd899415ea56b5417725

documentation/ref-manual/ref-variables.rst

@@ -665,7 +665,7 @@ system and gives an overview of their function and contents.
       environment: export BBSERVER=localhost:$port
    
       By default, ``BBSERVER`` also appears in
-      ```BB_HASHBASE_WHITELIST`` <&YOCTO_DOCS_BB_URL;#var-BB_HASHBASE_WHITELIST>`__.
+      :term:`bitbake:BB_HASHBASE_WHITELIST`.
       Consequently, ``BBSERVER`` is excluded from checksum and dependency
       data.
    
@@ -5829,7 +5829,7 @@ system and gives an overview of their function and contents.
       excludes the following variables:
       :term:`CONF_VERSION`
       :term:`BB_NUMBER_THREADS`
-      `BB_NUMBER_PARSE_THREADS <&YOCTO_DOCS_BB_URL;#var-BB_NUMBER_PARSE_THREADS>`__
+      :term:`bitbake:BB_NUMBER_PARSE_THREADS`
       :term:`PARALLEL_MAKE`
       :term:`PRSERV_HOST`
       :term:`SSTATE_MIRRORS` :term:`DL_DIR`