Configure error: SNDFILE not found?

Hi,

sorry if I'm being basic but I'm new to linux.

When I attempt to configure samplv1 and drumkv1 I get the message:

homer@homer-Precision-3510:~/Music/plugins/samplv1-0.8.1$ ./configure --with-qt5=/home/homer/Qt/5.8/gcc_64
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
checking for g++... g++
checking whether we are using the GNU C++ compiler... yes
checking whether g++ accepts -g... yes
checking how to run the C++ preprocessor... g++ -E
checking for pkg-config... /usr/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for g++ major version... 5
checking for qmake-qt5... /home/homer/Qt/5.8/gcc_64/bin/qmake-qt5
checking for Qt major version... 5
checking for Qt install path... /home/homer/Qt/5.8/gcc_64/bin
checking for qmake... /home/homer/Qt/5.8/gcc_64/bin/qmake
checking for Qt install headers... /home/homer/Qt/5.8/gcc_64/include
checking for Qt install libraries... /home/homer/Qt/5.8/gcc_64/lib
checking for Qt library version >= 5.1... yes
checking for moc... /home/homer/Qt/5.8/gcc_64/bin/moc
checking for uic... /home/homer/Qt/5.8/gcc_64/bin/uic
checking for lupdate... /home/homer/Qt/5.8/gcc_64/bin/lupdate
checking for lrelease... /home/homer/Qt/5.8/gcc_64/bin/lrelease
checking for main in -lm... yes
checking for main in -lX11... no
checking for main in -lXext... no
checking for SNDFILE... no
configure: error: *** SNDFILE library not found.

Can anybody help?

Also having problem with qsampler, it says LSCP library not found - I've posted in qsampler forum as well.

Thanks

Jack