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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def generate(env):
 """Add Builders and construction variables for sun f90 compiler to an Environment."""

    add_all_to_env(env)

    fcomp = env.Detect(compilers) or 'f90'
    env['FORTRAN']  = fcomp
    env['F90']      = fcomp

    env['SHFORTRAN']  = '$FORTRAN'
    env['SHF90']      = '$F90'

    env['SHFORTRANFLAGS'] = SCons.Util.CLVar('$FORTRANFLAGS -KPIC')
    env['SHF90FLAGS'] = SCons.Util.CLVar('$F90FLAGS -KPIC')