CPU feature checking - require SSE2

 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 SSE2 and refuses to install
 on unsupported hardware.
 .
 Streaming SIMD Extensions (SSE) is a single instruction, multiple data
 (SIMD) instruction set extension.
 .
 SSE2 was an incremental upgrade to SSE intended to fully replace the earlier
 MMX instruction set. It is available on processors from Pentium 4 onward,
 including all 64-bit capable ones, but not on Pentium 3, Athlon XP, Via C3,
 Quark, or older processors.