LO 5.1 build broken

Hi,

LO 5.1 is currently broken. I get the following error message:

> [build LOC] libreoffice
> [build LOC] top level modules: libreoffice
> /home/jbf/LibO/lo51/workdir/CxxObject/sc/source/ui/view/reffact.o: In function 
> `ScValidationDlg::Close()':
> reffact.cxx:(.text._ZN15ScValidationDlg5CloseEv[_ZN15ScValidationDlg5CloseEv]+0x36): undefined 
> reference to `ScTPValidationValue::RemoveRefDlg()'
> /home/jbf/LibO/lo51/workdir/CxxObject/sc/source/ui/view/reffact.o: In function 
> `ScValidationDlg::dispose()':
> reffact.cxx:(.text._ZN15ScValidationDlg7disposeEv[_ZN15ScValidationDlg7disposeEv]+0x10): 
> undefined reference to `ScValidationDlg::RemoveRefDlg(bool)'
> collect2: error: ld returned 1 exit status
> /home/jbf/LibO/lo51/sc/Library_sc.mk:10: recipe for target 
> '/home/jbf/LibO/lo51/instdir/program/libsclo.so' failed
> make[1]: *** [/home/jbf/LibO/lo51/instdir/program/libsclo.so] Error 1
> Makefile:244: recipe for target 'build' failed
> make: *** [build] Error 2

My last successful build was incremental and for this buildID:
Version: 5.1.0.0.beta2+
Build ID: 8f63516df72b49e9347d90750f6d3ef3d4a1813f
Threads 4; Ver: 4.2; Render: default;
Ubuntu_15.10_x86-64
Locale : fr-FR (fr_FR.UTF-8)

Last night I did a complete rebuild (make distclean -> ./autogen.sh ->
make). I just changed optimization option from -O2 to -O3 for gcc
(version 5.2). What I do not undeerstand is why, when I reset my local
repository to commit 8f63516df72b49e9347d90750f6d3ef3d4a1813f, now I get
the same build error. Is it possible that the cause could be the change
I made for the optimization level?

Best regards.
JBF

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