Compilation fails for 'classic_armv7_a7' because of 'FLAGS' instead of 'CFLAGS'

[DrUm78]

Compilation fails for 'classic_armv7_a7'. Indeed, it seems like CFLAGS should be used instead of FLAGS below (works for me):

beetle-ngp-libretro/Makefile

Line 128 in 673c3d9

FLAGS += -DARM -Ofast \

Stack:

during RTL pass: expand
libretro.c: In function ‘retro_run’:
libretro.c:561:6: internal compiler error: in arm_expand_divmod_libfunc, at config/arm/arm.c:33047
  561 | void retro_run(void)
      |      ^
0x7f52f6930082 __libc_start_main
        ../csu/libc-start.c:308
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lto-wrapper: fatal error: /opt/FunKey-sdk/bin/arm-funkey-linux-musleabihf-g++.br_real returned 1 exit status
compilation terminated.
/opt/FunKey-sdk/bin/../lib/gcc/arm-funkey-linux-musleabihf/10.2.0/../../../../arm-funkey-linux-musleabihf/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status
make: *** [Makefile:659: mednafen_ngp_libretro.so] Error 1