#### G.1.2 Build Tools

The following tools are required:

C++, C, and Fortran compilers
  The Octave sources are primarily written in C++, but some portions are also written in C and Fortran. The Octave sources are intended to be portable. Recent versions of the GNU compiler collection (GCC) should work (http://gcc.gnu.org). If you use GCC, you should avoid mixing versions. For example, be sure that you are not using the obsolete `g77` Fortran compiler with modern versions of `gcc` and `g++`.
GNU Make
  Tool for building software (http://www.gnu.org/software/make). Octave's build system requires GNU Make. Other versions of Make will not work. Fortunately, GNU Make is highly portable and easy to install.
AWK, sed, and other Unix utilities
  Basic Unix system utilities are required for building Octave. All will be available with any modern Unix system and also on Windows with either Cygwin or MinGW and MSYS.

Additionally, the following tools may be needed:

Bison
  Parser generator (http://www.gnu.org/software/bison). You will need Bison if you modify the `oct-parse.yy` source file or if you delete the files that are generated from it.
Flex
  Lexer analyzer (http://www.gnu.org/software/flex). You will need Flex if you modify the `lex.ll` source file or if you delete the files that are generated from it.
Autoconf
  Package for software configuration (http://www.gnu.org/software/autoconf). Autoconf is required if you modify Octave's `configure.ac` file or other files that it requires.
Automake
  Package for Makefile generation (http://www.gnu.org/software/automake). Automake is required if you modify Octave's `Makefile.am` files or other files that they depend on.
Libtool
  Package for building software libraries (http://www.gnu.org/software/libtool). Libtool is required by Automake.