Something

make[4]: Entering directory `/home/zapek/src/gstreamer/gstreamer/gst/parse'
/usr/bin/bison -d -v -p_gst_parse_yy ./grammar.y -o grammar.tab.c && \
        mv grammar.tab.c grammar.tab_tmp.c && \
        echo '#ifdef HAVE_CONFIG_H' > grammar.tab_tmp2.c && \
        echo '#include <config.h>' >> grammar.tab_tmp2.c && \
        echo '#endif' >> grammar.tab_tmp2.c && \
        cat grammar.tab_tmp.c >> grammar.tab_tmp2.c && \
        rm grammar.tab_tmp.c && \
        mv grammar.tab_tmp2.c grammar.tab.c
./grammar.y: conflicts: 37 shift/reduce, 5 reduce/reduce
/usr/bin/flex -P_gst_parse_yy lex._gst_parse_yy.c && \
        mv lex._gst_parse_yy.c lex._gst_parse_yy_tmp.c && \
        echo '#ifdef HAVE_CONFIG_H' > lex._gst_parse_yy_tmp2.c && \
        echo '#include <config.h>' >> lex._gst_parse_yy_tmp2.c && \
        echo '#endif' >> lex._gst_parse_yy_tmp2.c && \
        cat lex._gst_parse_yy_tmp.c >> lex._gst_parse_yy_tmp2.c && \
        rm lex._gst_parse_yy_tmp.c && \
        mv lex._gst_parse_yy_tmp2.c lex._gst_parse_yy.c
flex: can't open lex._gst_parse_yy.c
make[4]: *** [lex._gst_parse_yy.c] Error 1
make[4]: Leaving directory `/home/zapek/src/gstreamer/gstreamer/gst/parse'
make[3]: *** [all-recursive] Error 1
make[3]: Leaving directory `/home/zapek/src/gstreamer/gstreamer/gst'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/home/zapek/src/gstreamer/gstreamer/gst'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/zapek/src/gstreamer/gstreamer'
make: *** [all] Error 2
build failed, aborting..