Makefile: add sonic.cpp to fix the build.

src/Makefile

 speak_SOURCES = speak.cpp compiledict.cpp dictionary.cpp intonation.cpp \
 	readclause.cpp setlengths.cpp numbers.cpp synth_mbrola.cpp \
 	synthdata.cpp synthesize.cpp translate.cpp mbrowrap.cpp \
-	tr_languages.cpp voices.cpp wavegen.cpp phonemelist.cpp klatt.cpp
+	tr_languages.cpp voices.cpp wavegen.cpp phonemelist.cpp klatt.cpp \
+	sonic.cpp
 
 libespeak_SOURCES = speak_lib.cpp compiledict.cpp dictionary.cpp intonation.cpp \
 	readclause.cpp setlengths.cpp numbers.cpp synth_mbrola.cpp \
 	synthdata.cpp synthesize.cpp translate.cpp mbrowrap.cpp \
 	tr_languages.cpp voices.cpp wavegen.cpp phonemelist.cpp \
-	espeak_command.cpp event.cpp fifo.cpp $(WAVE) debug.cpp klatt.cpp
+	espeak_command.cpp event.cpp fifo.cpp $(WAVE) debug.cpp klatt.cpp \
+	sonic.cpp
 
 SRCS1=$(speak_SOURCES)
 OBJS1=$(patsubst %.cpp,%.o,$(SRCS1))

src/Makefile.espeakedit

     prosodydisplay.cpp readclause.cpp setlengths.cpp speak_lib.cpp spect.cpp \
     spectdisplay.cpp spectseq.cpp synthdata.cpp synthesize.cpp synth_mbrola.cpp \
     translate.cpp transldlg.cpp tr_languages.cpp voicedlg.cpp voices.cpp vowelchart.cpp \
-    wave.cpp wavegen.cpp
+    wave.cpp wavegen.cpp sonic.cpp
 
 OBJS=$(patsubst %.cpp,%.o,$(SRCS))