[U-Boot] GCC 5.x compile errors

[ANDY KENNEDY]

Attempted to build u-boot with gcc 5.x for mipsel 32.  Result was that
I get brokenness around arch/mips/include/asm/io.h and
arch/mips/include/asm/system.h.  The source lines all look something
like:

extern inline void func()
{
	func text ;
}

Question:  Is that valid C text?  I have never seen such.  Also, what
does this mean from a header file?  The way I read this is

extern = the following declare exists in global space (no code here)

inline = use this function definition in line in place of creating a
	   text ref section

I would expect these two to be mutually exclusive????

Please enlighten me!

Thanks,
Andy