Add doxygen version check

Check which version of doxygen is being used in
./scripts/run_doxygen.sh, and add a sentence to the documentation about
using the correct version.

The warnings produced by doxygen are different for different versions
of doxygen, so it is important, when comparing a list of expected
warnings, to use the right version of doxygen.

Author: John Nonweiler

doc/architectural/compilation-and-development.md

@@ -197,7 +197,9 @@ The doxygen documentation can be [accessed online](http://cprover.diffblue.com).
 To build it locally, run `scripts/run_doxygen.sh`.  HTML output will be created
 in `doc/html/`. The index page is `doc/html/index.html`.  This script will
 filter out expected warning messages from doxygen, so that new problems are more
-obvious.  In the event that any change fixes an old warning, then the
+obvious.  It is important to use the correct version of doxygen, as specified
+in `run_doxygen.sh`, so that there are no unexpected changes to the list of
+expected warnings.  In the event that any change fixes an old warning, then the 
 corresponding line(s) should be deleted from
 `scripts/expected_doxygen_warnings.txt`.  We want to avoid adding any more
 warnings to this list of expected warnings, but that can be done to work around

scripts/run_doxygen.sh

@@ -1,5 +1,15 @@
 #!/bin/bash
 
+# Check doxygen version
+EXPECTED_VERSION="1.8.14"
+doxygen --version | grep -x $EXPECTED_VERSION > /dev/null
+if [ $? -ne 0 ]
+then
+  echo "WARNING: Using wrong version of doxygen.\
+  The list of expected warnings is for version $EXPECTED_VERSION."
+fi
+
+# Run doxygen and filter warnings
 SCRIPT_FOLDER=`dirname $0`
 cd $SCRIPT_FOLDER/../src
 doxygen 2>&1 | ../scripts/filter_expected_warnings.py ../scripts/expected_doxygen_warnings.txt