fenv() support broken with GCC 10 on ARM

[Sebastian Huber]

Hello,

I get the following linker errors with GCC and the latest Newlib on ARM:

/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/bin/ld: 
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/lib/thumb/cortex-m3/libm.a(lib_a-fenv-vfp.o):/scratch/git-rtems-source-builder/rtems/build/arm-rtems6-gcc-50666d2-newlib-f095752-x86_64-linux-gnu-1/build/arm-rtems6/thumb/cortex-m3/newlib/targ-include/machine/fenv-softfloat.h:61: 
multiple definition of `__softfloat_float_rounding_mode'; 
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/lib/thumb/cortex-m3/libm.a(lib_a-fenv-softfp.o):/scratch/git-rtems-source-builder/rtems/build/arm-rtems6-gcc-50666d2-newlib-f095752-x86_64-linux-gnu-1/build/arm-rtems6/thumb/cortex-m3/newlib/targ-include/machine/fenv-softfloat.h:61: 
first defined here
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/bin/ld: 
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/lib/thumb/cortex-m3/libm.a(lib_a-fenv-vfp.o):/scratch/git-rtems-source-builder/rtems/build/arm-rtems6-gcc-50666d2-newlib-f095752-x86_64-linux-gnu-1/build/arm-rtems6/thumb/cortex-m3/newlib/targ-include/machine/fenv-softfloat.h:60: 
multiple definition of `__softfloat_float_exception_mask'; 
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/lib/thumb/cortex-m3/libm.a(lib_a-fenv-softfp.o):/scratch/git-rtems-source-builder/rtems/build/arm-rtems6-gcc-50666d2-newlib-f095752-x86_64-linux-gnu-1/build/arm-rtems6/thumb/cortex-m3/newlib/targ-include/machine/fenv-softfloat.h:60: 
first defined here
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/bin/ld: 
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/lib/thumb/cortex-m3/libm.a(lib_a-fenv-vfp.o):/scratch/git-rtems-source-builder/rtems/build/arm-rtems6-gcc-50666d2-newlib-f095752-x86_64-linux-gnu-1/build/arm-rtems6/thumb/cortex-m3/newlib/targ-include/machine/fenv-softfloat.h:59: 
multiple definition of `__softfloat_float_exception_flags'; 
/build/rtems/6/lib/gcc/arm-rtems6/10.1.1/../../../../arm-rtems6/lib/thumb/cortex-m3/libm.a(lib_a-fenv-softfp.o):/scratch/git-rtems-source-builder/rtems/build/arm-rtems6-gcc-50666d2-newlib-f095752-x86_64-linux-gnu-1/build/arm-rtems6/thumb/cortex-m3/newlib/targ-include/machine/fenv-softfloat.h:59: 
first defined here