But i have the 68882 fpu installed, is'nt this switch useful at all
(apart for the kernel)?
Well, it's useful for FPU code, that's it. Kernel, XaAES, most of other stuff in FreeMiNT CVS doesn't use FPU => you can't gain anything from it since the most visible optimization comes from the fact it uses FPU registers and instructions for arithmetic operations instead of software-emulated floating point numbers (which are slow as hell).
As mentioned, you are actually making your 030-only code slower with 020-60 because, in theory, -m68030 tells compiler "hey look, this CPU has 256 bytes cache, let's optimize loops for this size" while 020-60 isn't that clear (cache size varies from 256 B to 8 KB).
04 and the make error appear only after that release. So something is
changed in the sources. I'm just curious to know why the 020-60 switch
was working before and not now.
Actually, you are right. This behavior can be observed after Vincent's change / support for ColdFire CPU:
-ifneq ($(CPU),030)
-NOCFLAGS-mmu030.S = $(MODEL)
-endif
-CFLAGS-mmu030.S = -m68030
-ifneq ($(CPU),040)
-NOCFLAGS-mmu040.S = $(MODEL)
-endif
-CFLAGS-mmu040.S = -m68040
what basically means CPU flags are always the same as for C source files. To me it seems OK, to use famous _expression_, it's not a bug but a feature :)