Taken from Gentoo:
https://gitweb.gentoo.org/repo/gentoo.git/plain/kde-apps/libkface/files/libkface-16.11.80-opencv3.2-gentoo-3.1.patch

--- a/src/recognition-opencv-lbph/facerec_borrowed.h	2016-11-26 14:19:01.492645170 +0100
+++ b/src/recognition-opencv-lbph/facerec_borrowed.h.new	2016-11-26 14:19:17.655835794 +0100
@@ -141,7 +141,7 @@
     /*
      * Predict
      */
-    void predict(cv::InputArray src, cv::Ptr<cv::face::PredictCollector> collector, const int state = 0) const override;
+    void predict(cv::InputArray src, cv::Ptr<cv::face::PredictCollector> collector) const override;
 #endif
 
     /**
--- a/src/recognition-opencv-lbph/facerec_borrowed.cpp	2016-11-26 14:19:01.492645170 +0100
+++ b/src/recognition-opencv-lbph/facerec_borrowed.cpp.new	2016-11-26 14:19:29.184971765 +0100
@@ -380,7 +380,7 @@
 #if OPENCV_TEST_VERSION(3,1,0)
 void LBPHFaceRecognizer::predict(InputArray _src, int &minClass, double &minDist) const
 #else
-void LBPHFaceRecognizer::predict(cv::InputArray _src, cv::Ptr<cv::face::PredictCollector> collector, const int state) const
+void LBPHFaceRecognizer::predict(cv::InputArray _src, cv::Ptr<cv::face::PredictCollector> collector) const
 #endif
 {
     if(m_histograms.empty())
@@ -404,7 +404,7 @@
     minDist      = DBL_MAX;
     minClass     = -1;
 #else
-    collector->init((int)m_histograms.size(), state);
+    collector->init((int)m_histograms.size());
 #endif
 
     // This is the standard method
@@ -424,7 +424,7 @@
             }
 #else
             int label = m_labels.at<int>((int) sampleIdx);
-            if (!collector->emit(label, dist, state))
+            if (!collector->collect(label, dist))
             {
                 return;
             }
@@ -470,7 +470,7 @@
                 minClass = it->first;
             }
 #else
-            if (!collector->emit(it->first, mean, state))
+            if (!collector->collect(it->first, mean))
             {
                 return;
             }
@@ -523,7 +523,7 @@
             }
 #else
             // large is better thus it is -score.
-            if (!collector->emit(it->first, -score, state))
+            if (!collector->collect(it->first, -score))
             {
                 return;
             }