I am a beginners so please bear with me :) I have this code passed to me and I need to run it. when I compile I have this error:

make[2]: Entering directory `/home/sahar/NetBeansProjects/Welcome_1'
mkdir -p build/Debug/GNU-Linux-x86
rm -f build/Debug/GNU-Linux-x86/classifier.o.d
gcc    -c -g -MMD -MP -MF build/Debug/GNU-Linux-x86/classifier.o.d -o build/Debug/GNU-Linux-x86/classifier.o classifier.c
In file included from classifier_utils.h:3:0,
                 from classifier.h:3,
                 from classifier.c:1:
memory_poll.h:5:28: fatal error: unicode/utrans.h: No such file or directory
compilation terminated.
make[2]: *** [build/Debug/GNU-Linux-x86/classifier.o] Error 1
make[2]: Leaving directory `/home/sahar/NetBeansProjects/Welcome_1'
make[1]: *** [.build-conf] Error 2
make[1]: Leaving directory `/home/sahar/NetBeansProjects/Welcome_1'
make: *** [.build-impl] Error 2
I searched and I found it is because the library I want to insert is some how not reachable. now my questions are:

1) I tried to install the libraries by apt-get install build-essential
it downloaded and installed but the code still doesnt work.

2) I dont know what is this library for? where can I find a list of C libraries and their specifications or a summery about them. like an API or something.

3) I have a lot of libraries like this, so, where can I find the list of libraries that my system has?

4)can you explain me step by step, how can I solve this error?

Thank you so much!