Remove __gnu89_inline.
Now that we use C99 almost everywhere, just use C99-style in the pmap
code. Since the pmap code is the only consumer of __gnu89_inline, remove
it from cdefs.h as well. Because the flag was only introduced 17 months
ago, I don't expect any problems.
Reviewed by: alc
It was backed out, because it prevented us from building kernels using a
7.x compiler. Now that most people use 8.x, there is nothing that holds
us back. Even if people run 7.x, they should be able to build a kernel
if they run `make kernel-toolchain' or `make buildworld' first.
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