CPU feature checking - require SSE4.1

 The packages in the isa-support family probe for microprocessor Instruction
 Set Architecture features such as SSE3. By refusing to install on machines
 lacking a required feature, they allow ISA requirements to be handled in
 terms of package dependencies.
 .
 This is a mostly dummy package which checks for SSE4.1 and refuses to install
 on unsupported hardware.
 .
 Streaming SIMD Extensions (SSE) is a single instruction, multiple data
 (SIMD) instruction set extension.
 .
 SSE4.1 added a dot product instruction and additional integer instructions.
 It is available on Intel processors since Penryn (circa 2008), but notably
 not on anything AMD until the Bulldozer (15h, in 2011) and Jaguar (16h, in
 2013) families.