I have installed all the necessary  packages for SWObjects compilation. While I issue the following command according to the instructions provided, I get the following error: 

venkates@Aravind:~/swobjects$ make bin/SWtransformer
(echo -e -n tests/test_SPARUL.dep tests/\\; g++ -DYYTEXT_POINTER=1 -fPIC -g -O0 -W -Wall -Wextra -Wnon-virtual-dtor -ansi -std=c++98 -I/home/venkates/swobjects -I/home/venkates/swobjects/lib   -I/home/venkates/swobjects/MapSetParser -I/home/venkates/swobjects/SPARQLfedParser -I/home/venkates/swobjects/SQLParser -I/home/venkates/swobjects/TrigSParser -I/home/venkates/swobjects/TurtleSParser -I/home/venkates/swobjects/lib -pipe  -MM tests/test_SPARUL.cpp) > tests/test_SPARUL.dep || (rm tests/test_SPARUL.dep; false)
In file included from tests/../tests/SPARQLTest.hpp:29,
                 from tests/test_SPARUL.cpp:9:
tests/../tests/../interface/SAXparser_expat.hpp:14:21: error: expat.h: No such file or directory

I would be glad if you could help me out with this.