View source for Build GCC-4.9.1 under Ubuntu 14.04

Follow the steps:

* Run the command:
  
  $ cd

* Download the source code for gcc-4.9.1:

   https://ftp.gnu.org/gnu/gcc/gcc-4.9.1/gcc-4.9.1.tar.bz2

* Create a new folder:

   $ mkdir gcc

* Copy the archive in the folder:

   $ cp ~/Downloads/gcc-4.9.1.tar.bz2 gcc

* Extract the archive:
  
   $ cd gcc
   $ tar -jxvf gcc-4.9.1.tar.bz2

* Change the current directory to gcc source folder and run the following command:

   $ cd gcc-4.9.1
   $ ./contrib/download_prerequisites

* Return to the previous folder:

   $ cd ..

* Create a new folder

   $ mkdir build

* Change the current directory to build:

   $ cd build

* Configure and build:

   $ sudo /home/<username>/gcc/gcc-4.9.1/configure --disable-multilib
   $ sudo make
   $ sudo make install