PATCH -- Fix degree trignometric functions

[Andreas Schwab]

FAIL: gfortran.dg/dec_math_5.f90   -O0  (test for excess errors)
Excess errors:
/opt/gcc/gcc-20200408/gcc/testsuite/gfortran.dg/dec_math_5.f90:132:9: Fatal Error: Cannot open module file 'ieee_arithmetic.mod' for reading at (1): No such file or directory
compilation terminated.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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