Make bswap.h handle being included outside an 'extern "C"' block:
all system headers are included first, then all declarations are
put inside an 'extern "C"' block.
This requires a little rearrangement as currently we have an ifdef
ladder that has some system includes and some local declarations
or definitions, and we need to separate those out.
We want to do this because dis-asm.h includes bswap.h, dis-asm.h
may need to be included from C++ files, and system headers should
not be included within 'extern "C"' blocks.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
b30a8c241f