Build fails due to doxygen segfault

[inkybutton]

The website build has been failing since 10 April, due to a doxygen segfault when building Iron API documentation.
Tail of most recent build log:

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Error in file /home/opencmiss-website-bb/opencmiss-website/webbuild-staging/webdir/apidoc/.working/iron/src/field_access_routines.f90 line: 808, state: 19

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/home/opencmiss-website-bb/opencmiss-website/webbuild-staging/webdir/apidoc/.working/iron/src/field_IO_routines.f90:6: warning: multiple use of section label 'LICENSE' while adding section, (first occurrence: /home/opencmiss-website-bb/opencmiss-website/webbuild-staging/webdir/apidoc/.working/iron/src/advection_diffusion_equation_routines.f90, line 5)
/home/opencmiss-website-bb/opencmiss-website/webbuild-staging/webdir/apidoc/.working/iron/src/field_routines.f90:5: warning: multiple use of section label 'LICENSE' while adding section, (first occurrence: /home/opencmiss-website-bb/opencmiss-website/webbuild-staging/webdir/apidoc/.working/iron/src/advection_diffusion_equation_routines.f90, line 5)

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Error in file /home/opencmiss-website-bb/opencmiss-website/webbuild-staging/webdir/apidoc/.working/iron/src/field_routines.f90 line: 32348, state: 19

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Segmentation fault (core dumped)
make[1]: *** [ironapi] Error 139

This may be related to OpenCMISS/iron#132 or OpenCMISS/iron#131 which were merged on the same day.

[inkybutton]

I've checked out Iron and built API documentation in the tree to find out what might be causing the segfault. It seems to be caused by changes to https://github.com/OpenCMISS/iron/blob/develop/src/field_routines.f90.
First bad commit seems to be: OpenCMISS/iron@a8bbe03#diff-2c265380a622f1bc06030e6d728ff02f
There seems to be a lot of changes in the commit. @chrispbradley do you have any idea what in the commit might be causing the problem?
EDIT - there are times when mesh_access_routines.f90 also seems to cause segfault but I could not duplicate it.

[inkybutton]

Hi @chrispbradley do you mind if I change this bug's assignment to you? Could take a look when you have time.