fix frange_nextafter odr violation

fix frange_nextafter odr violation

C++ requires inline functions to be declared inline and defined in
every translation unit that uses them.  frange_nextafter is used in
gimple-range-op.cc but it's only defined as inline in
range-op-float.cc.  Drop the extraneous inline specifier.

Other non-static inline functions in range-op-float.cc are not
referenced elsewhere, so I'm making them static.

for  gcc/ChangeLog

	* range-op-float.cc (frange_nextafter): Drop inline.
	(frelop_early_resolve): Add static.
	(frange_float): Likewise.