RPM spec for RedHat Linuxes

A spec for building an RPM for ruby-xz. Many thanks to @jsomara for providing this!.

%global gem_name ruby-xz
%if 0%{?rhel} == 6
%global gem_dir %(ruby -rubygems -e 'puts Gem::dir' 2>/dev/null)
%global gem_instdir %{gem_dir}/gems/%{gem_name}-%{version}
%global gem_docdir %{gem_dir}/doc/%{gem_name}-%{version}
%global gem_cache %{gem_dir}/cache/%{gem_name}-%{version}.gem
%global gem_spec %{gem_dir}/specifications/%{gem_name}-%{version}.gemspec
%global gem_libdir %{gem_instdir}/lib
%endif

Summary: XZ compression via liblzma for Ruby
Name: rubygem-%{gem_name}
Version: 0.1.1
Release: 2%{?dist}
Group: Development/Languages
License: GPLv2+ or Ruby
Source0: http://rubygems.org/gems/%{gem_name}-%{version}.gem
Requires: ruby(rubygems)
Requires: rubygem(ffi)
Requires: rubygem(io-like)
Requires: xz-devel
BuildRequires: rubygems
BuildRequires: rubygem(rake)
BuildArch: noarch
Provides: rubygem(%{gem_name}) = %{version}
%if 0%{?rhel} == 6 || 0%{?fedora} < 17
Requires: ruby(abi) = 1.8
%else
Requires: ruby(abi) = 1.9.1
%endif
%if 0%{?fedora}
BuildRequires: rubygems-devel
%endif

%description
This is a basic binding for liblzma that allows you to
create and extract XZ-compressed archives. It can cope with big
files as well as small ones, but doesn't offer much
of the possibilities liblzma itself has.


%package doc
Summary: Documentation for %{name}
Group: Documentation
Requires: %{name} = %{version}-%{release}
BuildArch: noarch

%description doc
Documentation for %{name}

%prep
gem unpack %{SOURCE0}
%setup -q -D -T -n %{gem_name}-%{version}
gem spec %{SOURCE0} -l --ruby > %{gem_name}.gemspec

%build
mkdir -p .%{gem_dir}
gem build %{gem_name}.gemspec
#rake ldap_fluff:gem

gem install -V \
        --local \
        --install-dir ./%{gem_dir} \
        --force \
        --rdoc \
        %{gem_name}-%{version}.gem


%install
mkdir -p %{buildroot}%{gem_dir}
cp -a ./%{gem_dir}/* %{buildroot}%{gem_dir}/

%files
%dir %{gem_instdir}
%{gem_libdir}
%exclude %{gem_cache}
%{gem_spec}
%{gem_instdir}/VERSION

%files doc
%doc %{gem_docdir}
%doc %{gem_instdir}/README.rdoc
%doc %{gem_instdir}/HISTORY.rdoc

%changelog
* Thu Feb 14 2013 Jordan OMara - 0.1.1-1
- Initial package