Compilation errors

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

Hello everybody,

I've made hundreds of Linux builds and never had problems, but since 
few days I'm not anymore able to compile the kernel with GCC or Clang.

I get many errors like the following and the build crashes:

# CC=gcc-11 make -j12
[...]
drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c: In function ‘bnx2x_check_blocks_with_parity3’:
drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c:4917:4: error: case label does not reduce to an integer constant
    case AEU_INPUTS_ATTN_BITS_MCP_LATCHED_SCPAD_PARITY:
[...]
make[5]: *** [scripts/Makefile.build:289: drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.o] Error 1
make[4]: *** [scripts/Makefile.build:551: drivers/net/ethernet/broadcom/bnx2x] Error 2
make[4]: *** Waiting for unfinished jobs....

One more example...

# make mrproper
# CC=clang make -j12
[...]
drivers/usb/typec/tcpm/tcpm.c:4724:3: error: case label does not reduce to an integer constant
   case BDO_MODE_TESTDATA:
   ^~~~
make[4]: *** [scripts/Makefile.build:288: drivers/usb/typec/tcpm/tcpm.o] Error 1
make[3]: *** [scripts/Makefile.build:550: drivers/usb/typec/tcpm] Error 2
make[2]: *** [scripts/Makefile.build:550: drivers/usb/typec] Error 2
make[2]: *** Waiting for unfinished jobs....

Can someone help me to understand what is happening and how to fix this issue?
Could it depend on a configuration option that, unintentionally enabled, make 
the build fail whenever "case label does not reduce to an integer constant" is 
hit? If so, which option?

Thanks,

Fabio M. De Francesco