sr_plan broken on PG 12

It looks like sr_plan needs to be adjusted for the new table access methods work from Andres.:

make USE_PGXS=1
gcc -std=gnu99 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -g -O2 -fPIC -I. -I./ -I/usr/local/pgsql/include/server -I/usr/local/pgsql/include/internal  -D_GNU_SOURCE -I/usr/include/libxml2   -c -o sr_plan.o sr_plan.c -MMD -MP -MF .deps/sr_plan.Po
sr_plan.c: In function ‘lookup_plan_by_query_hash’:
sr_plan.c:397:2: warning: implicit declaration of function ‘index_getnext’ [-Wimplicit-function-declaration]
  while ((htup = index_getnext(query_index_scan, ForwardScanDirection)) != NULL)
  ^
sr_plan.c:397:15: warning: assignment makes pointer from integer without a cast [enabled by default]
  while ((htup = index_getnext(query_index_scan, ForwardScanDirection)) != NULL)
               ^
sr_plan.c: In function ‘sr_planner’:
sr_plan.c:551:3: error: too few arguments to function ‘index_fetch_heap’
   htup = index_fetch_heap(query_index_scan);
   ^
In file included from /usr/local/pgsql/include/server/access/amapi.h:15:0,
                 from /usr/local/pgsql/include/server/access/hash.h:20,
                 from sr_plan.c:9:
/usr/local/pgsql/include/server/access/genam.h:164:13: note: declared here
 extern bool index_fetch_heap(IndexScanDesc scan, struct TupleTableSlot *slot);
             ^
sr_plan.c: In function ‘sr_query_expr_walker’:
sr_plan.c:716:29: error: ‘List’ has no member named ‘head’
    param->node = fexpr->args->head->data.ptr_value;
                             ^
sr_plan.c:738:17: error: ‘List’ has no member named ‘head’
      fexpr->args->head->data.ptr_value = param->node;
                 ^
sr_plan.c: In function ‘make_tupledesc’:
sr_plan.c:910:2: error: too many arguments to function ‘CreateTemplateTupleDesc’
  tupdesc = CreateTemplateTupleDesc(1, false);
  ^
In file included from /usr/local/pgsql/include/server/executor/tuptable.h:19:0,
                 from /usr/local/pgsql/include/server/nodes/print.h:17,
                 from sr_plan.h:8,
                 from sr_plan.c:1:
/usr/local/pgsql/include/server/access/tupdesc.h:94:18: note: declared here
 extern TupleDesc CreateTemplateTupleDesc(int natts);
                  ^
postgrespro / sr_plan

sr_plan broken on PG 12 #2
