[Qgis-developer] Building QGIS2.99 cloned from GitHub on Ubuntu 16.10 (yakkety) 64-bit Python

[gordon at shieldaig.com]

Due to previous error, mentioned in a early post, I installed `geos 
3.6.1` and because build still failed, I place header file `geos_c.h` in 
src/core/geometry folder and replace `<geos_c.h>` with `"geos_c.h"` in 
`qgsgeometry.h`.  This may not have been necessary but I wanted to make 
it clear which header I expected to be used.

At about 16% output from build shows:
`/home/gordon/dev/cpp/QGIS/src/core/qgsvectorfilewriter.cpp: In member 
function ‘void QgsVectorFileWriter::init(QString, QString, const 
QgsFields&, QgsWkbTypes::Type, QgsCoordinateReferenceSystem, const 
QString&, QStringList, QStringList, QString*, 
QgsVectorFileWriter::FieldValueConverter*, const QString&, 
QgsVectorFileWriter::ActionOnExistingFile)’:
/home/gordon/dev/cpp/QGIS/src/core/qgsvectorfilewriter.cpp:327:55: 
warning: suggest braces around empty body in an ‘else’ statement 
[-Wempty-body]
      QgsDebugMsg( "Opened data source in update mode" );`
                                                        ^
At about 90% output from build shows:
`Traceback (most recent call last):
   File "../../../../scripts/pyuic-wrapper.py", line 26, in <module>
     import qgis.PyQt.uic.pyuic
   File "/home/gordon/dev/cpp/QGIS/build/output/python/qgis/__init__.py", 
line 28, in <module>
     from qgis.core import QgsFeature, QgsGeometry
   File 
"/home/gordon/dev/cpp/QGIS/build/output/python/qgis/core/__init__.py", 
line 34, in <module>
     from qgis._core import *
ImportError: /usr/lib/x86_64-linux-gnu/libQt5Network.so.5: symbol 
_Z15qIsEffectiveTLDRK7QString, version Qt_5 not defined in file 
libQt5Core.so.5 with link time reference
python/plugins/db_manager/CMakeFiles/zzz-db_manager-15-depend.dir/build.make:72: 
recipe for target 'python/plugins/db_manager/ui_DlgAddGeometryColumn.py' 
failed
make[2]: *** [python/plugins/db_manager/ui_DlgAddGeometryColumn.py] 
Error 1
CMakeFiles/Makefile2:4925: recipe for target 
'python/plugins/db_manager/CMakeFiles/zzz-db_manager-15-depend.dir/all' 
failed
make[1]: *** 
[python/plugins/db_manager/CMakeFiles/zzz-db_manager-15-depend.dir/all] 
Error 2
make[1]: *** Waiting for unfinished jobs....`

Anyone know how to fix this issue?  I used Python3.

At about 95% `make -j3` terminated before `qgis` executable built.

Gordon