More thorough use of configure parameters

Make sure we explicitly either --enable/--with or --disable/--without
every possible feature.  This ensures that plugins/features are not
accidentally built or omitted.

Explicitly enable or disable VDDK depending on architecture (although
the configure script does this already so it's not really necessary).
If we ever build VDDK for Arm then we will have to revisit this.

We can now disable the torrent plugin through configure so we don't
have to delete the plugin afterwards.

nbdkit.spec

@@ -680,24 +680,52 @@ autoreconf -i
 # package into their vendor/ directory.
 export PYTHON=%{__python3}
 %configure \
-    --with-extra='%{name}-%{version}-%{release}' \
     --disable-static \
+    --with-extra='%{name}-%{version}-%{release}' \
+    --with-tls-priority=@NBDKIT,SYSTEM \
+    --with-bash-completions \
+    --with-curl \
+    --with-gnutls \
+    --with-liblzma \
+    --with-libnbd \
+    --with-manpages \
+    --with-selinux \
+    --with-ssh \
+    --with-zlib \
+    --enable-linuxdisk \
+    --enable-python \
     --disable-golang \
     --disable-rust \
+    --disable-valgrind \
 %if !0%{?rhel} && 0%{?have_ocaml}
     --enable-ocaml \
 %else
     --disable-ocaml \
 %endif
-%if 0%{?rhel}
+%if !0%{?rhel}
+    --enable-lua \
+    --enable-perl \
+    --enable-ruby \
+    --enable-tcl \
+    --enable-torrent \
+    --with-ext2 \
+    --with-iso \
+    --with-libvirt \
+%else
     --disable-lua \
     --disable-perl \
     --disable-ruby \
     --disable-tcl \
+    --disable-torrent \
     --without-ext2 \
     --without-iso \
     --without-libvirt \
 %endif
+%ifarch x86_64
+    --enable-vddk \
+%else
+    --disable-vddk \
+%endif
 %if !0%{?rhel} && 0%{?have_libguestfs}
     --with-libguestfs \
 %else
@@ -708,7 +736,7 @@ export PYTHON=%{__python3}
 %else
     --disable-libguestfs-tests \
 %endif
-    --with-tls-priority=@NBDKIT,SYSTEM
+    %{nil}
 
 # Verify that it picked the correct version of Python
 # to avoid RHBZ#1404631 happening again silently.
@@ -729,7 +757,7 @@ rm -f $RPM_BUILD_ROOT%{_mandir}/man3/nbdkit-rust-plugin.3*
 
 %if 0%{?rhel}
 # In RHEL, remove some plugins we cannot --disable.
-for f in cc cdi torrent; do
+for f in cc cdi ; do
     rm -f $RPM_BUILD_ROOT%{_libdir}/%{name}/plugins/nbdkit-$f-plugin.so
     rm -f $RPM_BUILD_ROOT%{_mandir}/man?/nbdkit-$f-plugin.*
 done