benchmark: Replace CFLAGS with CPPFLAGS where appropriate.
benchmark: Replace CFLAGS with CPPFLAGS where appropriate.

The NDEBUG macro is specified for the preprocessor not the compiler.

debug-de-su-ka/pal,olajep/pal,debug-de-su-ka/pal,mateunho/pal,eliteraspberries/pal,mateunho/pal,eliteraspberries/pal,aolofsson/pal,Adamszk/pal3,debug-de-su-ka/pal,debug-de-su-ka/pal,eliteraspberries/pal,8l/pal,8l/pal,aolofsson/pal,8l/pal,eliteraspberries/pal,aolofsson/pal,olajep/pal,parallella/pal,olajep/pal,mateunho/pal,mateunho/pal,mateunho/pal,parallella/pal,aolofsson/pal,Adamszk/pal3,debug-de-su-ka/pal,olajep/pal,8l/pal,Adamszk/pal3,eliteraspberries/pal,Adamszk/pal3,parallella/pal,parallella/pal,parallella/pal