compile error building building Python-3.8.5 on Debian 8.11 (yes, old!)

[Cameron Simpson]

I've built 3.8.5 on a few other machines happily recently.

Building Python 3.8.5, running make and gcc (Debian 4.9.2-10+deb8u2) 
4.9.2 I get this:

    % gcc -pthread -c -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall    -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration  -I./Include/internal  -I.  -I./Include    -DPy_BUILD_CORE -o Modules/gcmodule.o Modules/gcmodule.c
    Modules/gcmodule.c: In function 'collect.constprop':
    Modules/gcmodule.c:126:50: warning: array subscript is above array bounds [-Warray-bounds]
     #define GEN_HEAD(state, n) (&(state)->generations[n].head)
                                                      ^
    Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD'
             gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation));
                                               ^
    Modules/gcmodule.c:126:50: warning: array subscript is above array bounds [-Warray-bounds]
     #define GEN_HEAD(state, n) (&(state)->generations[n].head)
                                                      ^
    Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD'
             gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation));
                                               ^
    Modules/gcmodule.c:126:50: warning: array subscript is above array bounds [-Warray-bounds]
     #define GEN_HEAD(state, n) (&(state)->generations[n].head)
                                                      ^
    Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD'
             gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation));
                                               ^

Any thoughts?

I'll try a few other minor versions meanwhile...

Cheers,
Cameron Simpson <cs at cskk.id.au>