Only export symbols starting with razor_ in dynamic library.

Apart from being good practice to avoid clashes with higher-level
libraries and the application, this also fixes an obscure bug: The
gnulib library is used both by librazor (the dynamic library) and
by razor (the executable). In doing so, we want to have two separate
copies of the library despite the code duplication this involves.
Without the explicit limit to export only razor_ symbols, the razor
executable under mingw64 was picking up the getopt_long function
from librazor and the optind variable from libgnu which meant that
it did not see optind changing. Hiding librazor's copy of getopt
causes the linker to find libgnu's copy and everything works.

Note that under mingw librazor-#.dll still contains undocumented
(private) razor_ symbols but these will do no harm as long as nobody
tries to use them.

 %define _source_payload w9.gzdio

 %define _binary_payload w9.gzdio

 Name:      zap

 Summary:   Test package

 Group:     Test

 License:   GPL

 Version:   1

 Release:   1

 Source:    zap.tar

 BuildArch: noarch

 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)

 Prefix:    /usr

 %description

 Test package

 %prep

 %build

 %install

 mkdir -p $RPM_BUILD_ROOT/usr/bin

 touch $RPM_BUILD_ROOT/usr/bin/zap

 %clean

 %files

 /usr/bin/zap