Add support for building with IAR#276

Draft

bavison wants to merge 12 commits intoraspberrypi:developfrom

bavison:portability

Commits on Sep 13, 2022

Remove implicit conversions between function and data pointers
Ben Avison
committed
M_PI is a GNU extension to math.h, so define it locally if necessary
Ben Avison
committed
Adapt to lack of typeof in hw_set_alias and hw_clear_alias
Ben Avison
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Remove unreachable code
Ben Avison
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Avoid branch-past-initialisation warning
Ben Avison
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Fix undefined order of volatile accesses
Ben Avison
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Make conversion to uint32_t of negative constant explicit
Ben Avison
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Avoid using non-standard escape sequence in string literals
Ben Avison
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Do explicit conversion from floating point to integer
Ben Avison
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Wrap GCC pragmas in #ifdef __GNUC__
Ben Avison
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Explicitly convert between enum and integer
Ben Avison
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Remove unused static functions
Ben Avison
committed