The original commit intended to fix a warning by our code checker krazy.
The issue the code checkers criticized is that we use code which is
only understand by a single compiler and thus not portable.
However, even the reverted commit uses the non portable code but is
hiding the issue from the checker. Therefore it is not a real fix.
Also the reverted commit introduces project specific knowledge,
the IS_GNU macro which has more general replacements (GNUC).
Additionally other compilers than GNU's GCC may have support for the
used attribute (I thing clang and Intel have). These compilers were
excluded from using the special behaviour.
This reverts commit 8f7c5ce861fc3d9fe6b6e59a24da3249ce91cf88.