[PATCH v4 03/13] Compiler Attributes: remove unneeded tests

Attributes const and always_inline have tests around them which are unneeded, since they are supported by gcc >= 4.6, clang >= 3 and icc >= 13. https://godbolt.org/z/DFPq37 In the case of gnu_inline, we do not need to test for __GNUC_STDC_INLINE__ because, regardless of the current inlining

[PATCH v4 03/13] Compiler Attributes: remove unneeded tests

Attributes const and always_inline have tests around them which are unneeded, since they are supported by gcc >= 4.6, clang >= 3 and icc >= 13. https://godbolt.org/z/DFPq37 In the case of gnu_inline, we do not need to test for __GNUC_STDC_INLINE__ because, regardless of the current inlining