* makeutl.ads (Root_Environment): New variable, moved rom
gprbuild (Load_Standard_Base): New Boolean variable, moved
from gprbuild.
* prj-conf.adb (Check_Builder_Switches): New procedure to check
for switch --RTS in package Builder. If a runtime specified
by --RTS is a relative path name, but not a base name, then
find the path on the Project Search Path.
(Do_Autoconf): Call Check_Builder_Switches.
(Locate_Runtime): New procedure, moved from gprbuild, to get the
absolute paths of runtimes when they are not specified as a base name.
* prj-conf.ads (Locate_Runtime): New procedure, moved from gprbuild.