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