linking to libva by libvacodec fails

My C++ program uses libavcodec. When I'm compiling with below command, I get the following errors

g++ `cppunit-config --cflags` -D__STDC_CONSTANT_MACROS     -o dist/Debug/GNU-Linux/ferryport  -lxml2 -lpthread -lssl -lcrypto `cppunit-config --libs` `pkg-config --cflags --libs libv4l2` -lwebsockets -lbase -lblkid -lz -llzma `pkg-config --cflags --libs libavcodec` `pkg-config --cflags --libs libavutil` `pkg-config --cflags --libs libpulse` -lasound   -Wall

/usr/lib/x86_64-linux-gnu/libva.a(va.o): In function `va_openDriver':
/usr/bin/ld: cannot find -lpulse
/usr/bin/ld: cannot find -lasound
collect2: error: ld returned 1 exit status

Running ld -lpulse --verbose and ld -lasound --verbose revealed that linker found the respective .so files. I'm unable to find what I am doing wrong.