With profiledbootstrap and --with-build-config=bootstrap-lto, linemap_add
may create a macro map when we run out of line map space. This patch
changes start_location to UNKNOWN_LOCATION (0) in this case.
Tested with profiledbootstrap and --with-build-config=bootstrap-lto on
Linux/x86-64.
PR bootstrap/86872
* line-map.c (pure_location_p): Return true if linemap_lookup
returns NULL.
(linemap_add): Set start_location to 0 if we run out of line map
space.
From-SVN: r263845
cf806c7dc3