Currently, to use build2 you will need a C++ compiler with C++14 support.
This may be relaxed later to only require C++11. For now, gcc 4.9.0 or
later and clang 3.5.0 or later are known to work.

build2 is self-hosted, which means that unless you have obtained a pre-
built binary of build2 from somewhere else, you will need to bootstrap
it. To accomplish this, use the 'bootstrap' shell script found in the
root directory of the build2 project. The following is a recommended
sequence of steps:

1. Execute 'bootstrap' specifying the C++ compiler to be used if necessary
   (default is 'g++'). For example:

   $ ./bootstrap --cxx clang++-3.5

   Once the script completes successfully, the build2 binary is saved
   as 'build/b-boot'.

2. Next, build the build2 binary using the bootstrapped binary from step
   1 above, again specifying the C++ compiler if necessary, for example:

   $ build/b-boot config.cxx=clang++-3.5

   The result of this command is saved as 'build/b'.

3. Finally, rebuild the build2 binary using the binary built at step 2
   above, and verify that they are identical. For example:

   $ mv build/b build/b-prev
   $ build/b-prev config.cxx=clang++-3.5 clean
   $ build/b-prev config.cxx=clang++-3.5 configure update
   $ diff -b build/b build/b-prev