Setting up the igraph-0.7.1 in C is quite easy
Step 1: yum install gcc44 and above
# yum install gcc44 gcc44-c++ gcc44-gfortran
Step 2: Install libxml2 libraries
# yum install libxml2
Step 3: Download the igraph-0.7.1 from the igraph C site
# ./configure --prefix=/usr/local/igraph-0.7.1 # make -j 8 # make install