+ 386 In 32-bit x86 builds, when generating assembly modules,
+ use the 80386 instruction set only (the default x86 code
+ is more efficient, but requires at least a 486). Note:
+ This doesn't affect code generated by compiler, you're
+ likely to complement configuration command line with
+ suitable compiler-specific option.
+
+ no-sse2 Exclude SSE2 code paths from 32-bit x86 assembly modules.
+ Normally SSE2 extension is detected at run-time, but the
+ decision whether or not the machine code will be executed
+ is taken solely on CPU capability vector. This means that
+ if you happen to run OS kernel which does not support SSE2
+ extension on Intel P4 processor, then your application
+ might be exposed to "illegal instruction" exception.
+ There might be a way to enable support in kernel, e.g.
+ FreeBSD kernel can be compiled with CPU_ENABLE_SSE, and
+ there is a way to disengage SSE2 code paths upon application
+ start-up, but if you aim for wider "audience" running
+ such kernel, consider no-sse2. Both the 386 and
+ no-asm options imply no-sse2.