sysdep.c (__gnat_has_cap_sys_nice): New function to determine whether the current process has the CAP_SYS_NICE...

2017-09-06  Bob Duff  <duff@adacore.com>

	* sysdep.c (__gnat_has_cap_sys_nice): New function to determine
	whether the current process has the CAP_SYS_NICE capability.
	* s-taprop-linux.adb (Get_Ceiling_Support): Update this to allow
	ceiling priorities if the current process has the CAP_SYS_NICE
	capability.

From-SVN: r251777