the problem about using --macros

hello,everyone.
now i have one problem that the rpm --macros seems no work.

the command is as follow:

rpm -qi --rcfile=/usr/lib/rpm/rpmrc --macros="test.rpmmacros" --
specfile ltt-control/test.spec

now I want to use the test.rpmmacros directly, not by containing it in
the rcfile, and I
see that
Common options for all rpm modes:
--macros=<FILE:...> read <FILE:...> instead of default
file(s)
--rcfile=<FILE:...> read <FILE:...> instead of default
file(s)

So I think that it means that macros option can used to read the
macros files.
And I defined the BuildRequires: %{target_config}-cross-libopt-for-dev
in the spec file.
and %target_config is defined in the test.rpmmacros.
But when I run the command, it generates the error.
error: line 27: Dependency tokens must begin with alpha-numeric, '_'
or '/': BuildRequires: %{target_config}-cross-libopt-for-dev
error: query of specfile ltt-control/test.spec failed, can't parse

the macros defined in the test.rpmmacros seems cann't be checkd, and I
am puzzled.

if anyone has any suggestion, I would be so thankful for the advice!