The [spec file for
librdkafka](https://github.com/edenhill/librdkafka/blob/master/packaging/rpm/librdkafka.spec)
calls its package 'librdkafka-devel', not 'rdkafka-devel'. Searching the
web for 'rdkafka-devel RPM' turns up nothing, all the RPMs are named
'librdkafka-devel'.
Summary: Write-kafka plugin for collectd
Group: System Environment/Daemons
Requires: %{name}%{?_isa} = %{version}-%{release}
-BuildRequires: rdkafka-devel
+BuildRequires: librdkafka-devel
%description write_kafka
The write_kafka plugin sends values to kafka, a distributed messaging system.
%endif