+%bcond_with mmx # MMX instructions
+%bcond_with sse # SSE instructions
+%bcond_with sse2 # SSE2 instructions in CIE,two-table,ycbcr modules, sse2-* modules
+# sse4.1, avx2, f16c are optional (in separate modules)
+# sse2 is runtime-detected, but whole files are compiled with -msse2, so it's not optional