[Bug ada/80007] --disable-bootstrap with gnat-5 leads to failed gnat-7 build on aarch64

[tulipawn at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80007

--- Comment #5 from PeteVine <tulipawn at gmail dot com> ---
The repeated full ada bootstrap was successful at the same revision, using
identical flags and GNAT 5.4.0.

On the other hand, the failing build prints two warnings during the ada part:

g-debpoo.adb: In function ‘GNAT.DEBUG_POOLS.GET_SIZE’:
g-debpoo.adb:1418:8: warning: ‘SIZE_IN_STORAGE_ELEMENTS’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
g-debpoo.ads:295:7: note: ‘SIZE_IN_STORAGE_ELEMENTS’ was declared here

and

g-comlin.adb: In function ‘GNAT.COMMAND_LINE.FIND_LONGEST_MATCHING_SWITCH’:
g-comlin.adb:583:8: warning: ‘PARAM’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
g-comlin.adb:107:7: note: ‘PARAM’ was declared here

The error message read differently this time:

 7.0.1 20170311 (experimental) (aarch64-linux-gnu) Storage_Error stack overflow
or erroneous memory access