Fails to build with GDAL 2.5.0-beta1

Description

OTB 6.6.1 fails to build with GDAL 2.5.0-beta1:

/build/otb-6.6.1+dfsg/Modules/Core/Transform/src/otbGeoInformationConversion.cxx: In function 'int otb::GeoInformationConversion::ToEPSG(const string&)':
/build/otb-6.6.1+dfsg/Modules/Core/Transform/src/otbGeoInformationConversion.cxx:80:7: error: 'class OGRSpatialReference' has no member named 'Fixup'
   srs.Fixup();
       ^~~~~

From https://github.com/OSGeo/gdal/blob/v2.5.0beta1/gdal/MIGRATION_GUIDE.TXT:

removal of OSRFixup() and OSRFixupOrdering(): no longer needed since objects constructed are always valid

Steps to reproduce

Build PROJ 6.0.0
Build libgeotiff 1.5.1 with the above
Build GDAL 2.5.0-beta1 with the above
Build OTB 6.6.1 with the above

Configuration information

Debian unstable, otb (6.6.1+dfsg-1) with gdal (2.5.0~~beta1+dfsg-1~~exp1), libgeotiff (1.5.1-1~~exp3) & proj (6.0.0-1~~exp2).