[Bug libfortran/124668] STOP statement should probably flush OUTPUT_UNIT before issuing its message on ERROR_UNIT

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124668

--- Comment #4 from anlauf at gcc dot gnu.org ---
% GFORTRAN_UNBUFFERED_ALL=1 ./a.out > stop_1.out 2>&1
% cat stop_1.out 
 this is line:           1
 this is line:           2
 this is line:           3
 this is line:           4
 this is line:           5
 this is line:           6
 this is line:           7
 this is line:           8
 this is line:           9
 this is line:          10
ERROR STOP 12345

Error termination. Backtrace:
#0  0x401254 in ???
#1  0x401288 in ???
#2  0x7f952d6f433f in ???
#3  0x7f952d6f4408 in ???
#4  0x4010c4 in _start
        at ../sysdeps/x86_64/start.S:115
#5  0xffffffffffffffff in ???