Returns the include statement for the compiler to use.

def _make_compiler_include(precompile, extralinks):
    """Returns the include statement for the compiler to use."""
    base = """ifeq ($(FAM),ifort)
  include {2}/Makefile.ifort{0}{3}
else
ifeq ($(FAM),gfortran)
  include {2}/Makefile.gfortran{1}{3}
else
  include Makefile.error
endif
endif"""
    if extralinks is not None and len(extralinks) > 0:
        from os import path
        libs = []
        for i, link in enumerate(extralinks):
            #We can only include *directories* for the -I specification.
            if path.isdir(link):
                libs.append("-I$(LBD{0:d})".format(i))
        exlinks = "\n  FFLAGS += {}".format(' '.join(libs))
    else:
        exlinks = ""
        
    #We need to see whether to include the pre-compiler directive or not.    
    if precompile:
        insert = ["\n  FFLAGS += -fpp -save-temps -heap-arrays", "\n  FFLAGS += -cpp",
                  get_fortpy_templates(), exlinks]
        return base.format(*insert)
    else:
        return base.format("", "", get_fortpy_templates(), exlinks)