Modernize the RPM spec.

xasm.spec

@@ -3,11 +3,9 @@ Version: 3.2.1
 Release: 1
 Summary: 6502 cross-assembler
 License: Poetic
-Group: Applications/Programming
 Source: http://pfusik.github.io/xasm/xasm-%{version}.tar.gz
 URL: https://github.com/pfusik/xasm
 BuildRequires: dmd >= 2, asciidoc
-BuildRoot: %{_tmppath}/%{name}-root
 
 %description
 xasm is a 6502 cross-assembler with original syntax extensions.
@@ -21,14 +19,9 @@ xasm is a 6502 cross-assembler with original syntax extensions.
 make xasm xasm.1
 
 %install
-rm -rf $RPM_BUILD_ROOT
-make DESTDIR=$RPM_BUILD_ROOT prefix=%{_prefix} install
-
-%clean
-rm -rf $RPM_BUILD_ROOT
+make DESTDIR=%{buildroot} prefix=%{_prefix} install
 
 %files
-%defattr(-,root,root)
 %{_bindir}/xasm
 %{_mandir}/man1/xasm.1.gz