Minimum GCC version that officially supports C++11

What is the minimum version of GCC that officially supports the C++11 standard? I am asking this because I want to modify my Makefile.am so that it builds a certain target binary only when the system compiler supports C++11.

The Makefile pseudo-code would look something like this:

if GCC compiler version >= minimum GCC version that supports C++11
    bin_PROGRAMS += program_that_needs_cpp11_to_compile
endif