def METHOD_NAME(combination):
    global gcc_multilib_set
    os = os_unusual if os_unusual in combination else os_default
    compilers = compilers_unusual if compilers_unusual in combination else compilers_default
    compiler_flags = [x for x in combination if x in compiler_flag_unusuals]
    configure_flags = [x for x in combination if x in configure_flag_unusuals]
    malloc_conf = [x for x in combination if x in malloc_conf_unusuals]
    # Filter out unsupported configurations on OS X.
    if os == 'osx' and ('dss:primary' in malloc_conf or \
      'percpu_arena:percpu' in malloc_conf or 'background_thread:true' \
      in malloc_conf):
        return ""
    if len(malloc_conf) > 0:
        configure_flags.append('--with-malloc-conf=' + ",".join(malloc_conf))
    # Filter out an unsupported configuration - heap profiling on OS X.
    if os == 'osx' and '--enable-prof' in configure_flags:
        return ""
    # We get some spurious errors when -Warray-bounds is enabled.
    env_string = ('{} COMPILER_FLAGS="{}" CONFIGURE_FLAGS="{}" '
	'EXTRA_CFLAGS="-Werror -Wno-array-bounds"').format(
        compilers, " ".join(compiler_flags), " ".join(configure_flags))
    job = ""
    job += '    - os: %s\n' % os
    job += '      env: %s\n' % env_string
    if '-m32' in combination and os == 'linux':
        job += '      addons:'
        if gcc_multilib_set:
            job += ' *gcc_multilib\n'
        else:
            job += ' &gcc_multilib\n'
            job += '        apt:\n'
            job += '          packages:\n'
            job += '            - gcc-multilib\n'
            gcc_multilib_set = True
    return job