kissfft

USE flags

• alloca - Use alloca(3) instead of malloc(3) for memory management
• cpu_flags_x86_sse - Use the SSE instruction set
• openmp - Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
• test - Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
• tools - Build command line tools