Try this.
Simply Download file from http://pecl.php.net/package/bcompiler
Action :- Just make sure, you read output, At one point it will tell you where bcompiler.so file has been save.
root@linux# wget http://pecl.php.net/get/bcompiler-1.0.2.tgz
root@linux# tar -xvf bcompiler-1.0.2.tgz
root@linux# phpize
root@linux# ./configure
root@linux# make
root@linux# make install
root@linux# make test
If nothing has gone wrong than bcompiler.so file must have been placed to 'ext' directory..
Now Start using your bcompiler if everything was OK :)