Yeah, it's not that simple. It should never use "long" to hold DF data, for one thing, because "long" varies in size with DF's compilers, and DT can be compiled as a 32-bit or 64-bit binary to work with 32-bit DF. DT doesn't even have to be compiled with the same compiler as DF either.
Anyway, hooking into 64-bit processes has some non-trivial differences, not to mention the fact that DT uses completely different APIs on every platform already. DT has probably also hardcoded the layouts of some DF structures (vectors, strings, etc.) that vary between 32-bit and 64-bit DF, as well as between MSVC 2010 and 2015, which probably aren't trivial to change. There's also the question of keeping 32-bit compatibility, which arguably makes debugging far easier, but also complicates support for both architectures somewhat.
Unrelated: Here are OS X layouts that I generated with devel/export-dt-ini, after Quietust's fix (although that shouldn't make a difference on OS X). They are entirely
untested, but may work somewhat if you're lucky. The 64-bit one is entirely useless at the moment, but might work once DT supports 64-bit DF.
[info]
checksum=0x8fce00fb
version_name=v0.43.05 osx32
complete=true
[addresses]
cur_year_tick=0x01b66a48
current_year=0x01b66a40
dwarf_civ_index=0x01b68f68
dwarf_race_index=0x01b68f74
fortress_entity=0x01b6daac
historical_entities_vector=0x01b76e14
creature_vector=0x01b8a6b0
active_creature_vector=0x01b8a6bc
weapons_vector=0x01b8a75c
shields_vector=0x01b8a7a4
quivers_vector=0x01b8a7c8
crutches_vector=0x01b8a7ec
backpacks_vector=0x01b8a7f8
ammo_vector=0x01b8a804
flasks_vector=0x01b8a960
pants_vector=0x01b8ace4
armor_vector=0x01b8ad14
shoes_vector=0x01b8ad20
helms_vector=0x01b8ad2c
gloves_vector=0x01b8ad38
artifacts_vector=0x01b8ad8c
squad_vector=0x01c85594
activities_vector=0x01c855c4
fake_identities_vector=0x01c86a08
poetic_forms_vector=0x01c86aec
musical_forms_vector=0x01c86b04
dance_forms_vector=0x01c86b1c
occupations_vector=0x01c86b64
world_data=0x01c898c4
material_templates_vector=0x01c89ff8
inorganics_vector=0x01c8a004
plants_vector=0x01c8a01c
races_vector=0x01c8a0b8
itemdef_weapons_vector=0x01c8a0f8
itemdef_trap_vector=0x01c8a104
itemdef_toy_vector=0x01c8a110
itemdef_tool_vector=0x01c8a11c
itemdef_instrument_vector=0x01c8a230
itemdef_armor_vector=0x01c8a23c
itemdef_ammo_vector=0x01c8a248
itemdef_siegeammo_vector=0x01c8a254
itemdef_glove_vector=0x01c8a260
itemdef_shoe_vector=0x01c8a26c
itemdef_shield_vector=0x01c8a278
itemdef_helm_vector=0x01c8a284
itemdef_pant_vector=0x01c8a290
itemdef_food_vector=0x01c8a29c
language_vector=0x01c8a2b4
translation_vector=0x01c8a2cc
colors_vector=0x01c8e898
shapes_vector=0x01c8e8a4
reactions_vector=0x01c8e8bc
base_materials=0x01c8ee84
all_syndromes_vector=0x01c8f8f4
events_vector=0x01c8fe00
historical_figures_vector=0x01c8fe18
world_site_type=0x0044
active_sites_vector=0x00048200
[offsets]
word_table=0x001c
string_buffer_offset=0x0000
[word_offsets]
base=0x0000
noun_singular=0x0004
noun_plural=0x0008
adjective=0x000c
verb=0x0014
present_simple_verb=0x0018
past_simple_verb=0x001c
past_participle_verb=0x0020
present_participle_verb=0x0024
words=0x0008
word_type=0x0024
language_id=0x0034
[general_ref_offsets]
ref_type=0x0008
artifact_id=0x0004
item_id=0x0004
[race_offsets]
name_singular=0x0004
name_plural=0x0008
adjective=0x000c
baby_name_singular=0x0010
baby_name_plural=0x0014
child_name_singular=0x0018
child_name_plural=0x001c
pref_string_vector=0x004c
castes_vector=0x0064
pop_ratio_vector=0x0070
materials_vector=0x219c
flags=0x007c
tissues_vector=0x21a8
[caste_offsets]
caste_name=0x0004
caste_descr=0x0044
caste_trait_ranges=0x01a8
caste_phys_att_ranges=0x0c6c
baby_age=0x00ec
child_age=0x00f0
adult_size=0x0104
flags=0x02d4
body_info=0x02e0
skill_rates=0x03fc
caste_att_rates=0x0e80
caste_att_caps=0x0fb0
shearable_tissues_vector=0x10a8
extracts=0x1554
[hist_entity_offsets]
histfigs=0x0070
beliefs=0x06ac
squads=0x09b4
positions=0x0930
assignments=0x0958
assign_hist_id=0x0004
assign_position_id=0x000c
position_id=0x0004
position_name=0x0040
position_female_name=0x0048
position_male_name=0x0050
[hist_figure_offsets]
hist_race=0x0002
hist_name=0x0038
id=0x0094
hist_fig_info=0x00c0
reputation=0x002c
current_ident=0x0018
fake_name=0x0004
fake_birth_year=0x0050
fake_birth_time=0x0054
kills=0x0018
killed_race_vector=0x000c
killed_undead_vector=0x0048
killed_counts_vector=0x0054
[hist_event_offsets]
event_year=0x0004
id=0x0014
killed_hist_id=0x0018
[item_offsets]
item_type=0x0004
item_def=0x00a4
id=0x0018
general_refs=0x0028
stack_size=0x005c
wear=0x0070
mat_type=0x0080
mat_index=0x0084
maker_race=0x0088
quality=0x008a
[item_subtype_offsets]
sub_type=0x0008
name=0x0028
name_plural=0x002c
adjective=0x0030
[item_filter_offsets]
item_subtype=0x0002
mat_class=0x0004
mat_type=0x0006
mat_index=0x0008
[weapon_subtype_offsets]
single_size=0x0044
multi_size=0x0048
ammo=0x0040
melee_skill=0x003c
ranged_skill=0x003e
[armor_subtype_offsets]
layer=0x0008
mat_name=0x0034
other_armor_level=0x0038
armor_adjective=0x0038
armor_level=0x0040
chest_armor_properties=0x004c
pants_armor_properties=0x0054
other_armor_properties=0x0048
[material_offsets]
solid_name=0x0044
liquid_name=0x0048
gas_name=0x004c
powder_name=0x0050
paste_name=0x0054
pressed_name=0x0058
flags=0x00c8
inorganic_materials_vector=0x00cc
inorganic_flags=0x0010
[plant_offsets]
name=0x001c
name_plural=0x0020
name_leaf_plural=0x0034
name_seed_plural=0x002c
materials_vector=0x014c
flags=0x0014
[descriptor_offsets]
color_name=0x001c
shape_name_plural=0x0020
[health_offsets]
parent_id=0x0008
body_part_flags=0x000c
layers_vector=0x0014
number=0x0034
names_vector=0x003c
names_plural_vector=0x0048
layer_tissue=0x0004
layer_global_id=0x0034
tissue_name=0x000c
tissue_flags=0x0004
[dwarf_offsets]
first_name=0x0000
nick_name=0x0004
last_name=0x0008
custom_profession=0x003c
profession=0x0040
race=0x0044
flags1=0x008c
flags2=0x0090
flags3=0x0094
meeting=0x009c
caste=0x00a8
sex=0x00aa
id=0x00ac
animal_type=0x00b4
civ=0x00bc
specific_refs=0x00f8
squad_id=0x0110
squad_position=0x0114
recheck_equipment=0x0160
mood=0x01e8
birth_year=0x0208
birth_time=0x020c
pet_owner_id=0x0230
current_job=0x02f4
physical_attrs=0x03a4
body_size=0x047c
size_info=0x044c
curse=0x0554
curse_add_flags1=0x0540
turn_count=0x05c0
souls=0x0678
states=0x0608
labors=0x0694
hist_id=0x075c
artifact_name=0x063c
active_syndrome_vector=0x07a4
syn_sick_flag=0x0030
unit_health_info=0x0804
temp_mood=0x052c
counters1=0x0514
counters2=0x0530
counters3=0x05dc
limb_counters=0x0764
blood=0x0464
body_component_info=0x0304
layer_status_vector=0x0024
wounds_vector=0x0364
mood_skill=0x02f8
used_items_vector=0x0808
affection_level=0x000c
inventory=0x0280
inventory_item_mode=0x0004
inventory_item_bodypart=0x0006
[syndrome_offsets]
cie_effects=0x0004
cie_end=0x0014
cie_first_perc=0x0060
cie_phys=0x0078
cie_ment=0x0094
syn_classes_vector=0x0058
trans_race_id=0x006c
[unit_wound_offsets]
parts=0x0004
id=0x0004
layer=0x0006
general_flags=0x001c
flags1=0x003c
flags2=0x0040
effects_vector=0x002c
bleeding=0x0044
pain=0x0048
cur_pen=0x0070
max_pen=0x0072
[soul_details]
name=0x0004
orientation=0x0048
mental_attrs=0x006c
skills=0x01d8
preferences=0x01e4
personality=0x01f0
beliefs=0x0000
emotions=0x0018
goals=0x0024
goal_realized=0x0018
traits=0x0040
stress_level=0x00c4
[emotion_offsets]
emotion_type=0x0000
strength=0x0008
thought_id=0x000c
sub_id=0x0010
level=0x0014
year=0x0020
year_tick=0x0024
[job_details]
id=0x000c
mat_type=0x0028
mat_index=0x002c
mat_category=0x0040
on_break_flag=0x0011
sub_job_id=0x0044
reaction=0x0004
reaction_skill=0x0028
[squad_offsets]
id=0x0000
name=0x0004
alias=0x0040
members=0x0044
orders=0x0050
schedules=0x005c
sched_size=0x0020
sched_orders=0x0008
sched_assign=0x0014
alert=0x0068
carry_food=0x00d4
carry_water=0x00d6
ammunition=0x0098
ammunition_qty=0x000c
quiver=0x00a8
backpack=0x00ac
flask=0x00b0
armor_vector=0x0040
helm_vector=0x004c
pants_vector=0x0058
gloves_vector=0x0064
shoes_vector=0x0070
shield_vector=0x007c
weapon_vector=0x0088
uniform_item_filter=0x0004
uniform_indiv_choice=0x0020
[activity_offsets]
activity_type=0x0004
events=0x0008
participants=0x002c
sq_lead=0x0068
sq_skill=0x0070
sq_train_rounds=0x007c
pray_deity=0x0064
pray_sphere=0x0068
knowledge_category=0x0074
knowledge_flag=0x0078
perf_type=0x0064
perf_participants=0x0094
perf_histfig=0x000c
[valid_flags_2]
size=0
[invalid_flags_1]
size=9
1\name=a skeleton
1\value=0x00002000
2\name=a merchant
2\value=0x00000040
3\name=outpost liason or diplomat
3\value=0x00000800
4\name=an invader or hostile
4\value=0x00020000
5\name=an invader or hostile
5\value=0x00080000
6\name=resident, invader or ambusher
6\value=0x00600000
7\name=part of a merchant caravan
7\value=0x00000080
8\name="Dead, Jim."
8\value=0x00000002
9\name=marauder
9\value=0x00000010
[invalid_flags_2]
size=5
1\name="killed, Jim."
1\value=0x00000080
2\name=from the Underworld. SPOOKY!
2\value=0x00040000
3\name=resident
3\value=0x00080000
4\name=uninvited visitor
4\value=0x00400000
5\name=visitor
5\value=0x00800000
[invalid_flags_3]
size=1
1\name=a ghost
1\value=0x00001000
checksum=0x6ec138c5
version_name=v0.43.05 osx64
complete=true
[addresses]
cur_year_tick=0x101a05ef4
current_year=0x101a05eec
dwarf_civ_index=0x101a08688
dwarf_race_index=0x101a08694
fortress_entity=0x101a0eb38
historical_entities_vector=0x101a18468
creature_vector=0x101a2bd20
active_creature_vector=0x101a2bd38
weapons_vector=0x101a2be78
shields_vector=0x101a2bf08
quivers_vector=0x101a2bf50
crutches_vector=0x101a2bf98
backpacks_vector=0x101a2bfb0
ammo_vector=0x101a2bfc8
flasks_vector=0x101a2c280
pants_vector=0x101a2c988
armor_vector=0x101a2c9e8
shoes_vector=0x101a2ca00
helms_vector=0x101a2ca18
gloves_vector=0x101a2ca30
artifacts_vector=0x101a2cad8
squad_vector=0x101b297c8
activities_vector=0x101b29828
fake_identities_vector=0x101b2b638
poetic_forms_vector=0x101b2b800
musical_forms_vector=0x101b2b830
dance_forms_vector=0x101b2b860
occupations_vector=0x101b2b8f0
world_data=0x101b2f2e0
material_templates_vector=0x101b2fe00
inorganics_vector=0x101b2fe18
plants_vector=0x101b2fe48
races_vector=0x101b2ff80
itemdef_weapons_vector=0x101b30000
itemdef_trap_vector=0x101b30018
itemdef_toy_vector=0x101b30030
itemdef_tool_vector=0x101b30048
itemdef_instrument_vector=0x101b30270
itemdef_armor_vector=0x101b30288
itemdef_ammo_vector=0x101b302a0
itemdef_siegeammo_vector=0x101b302b8
itemdef_glove_vector=0x101b302d0
itemdef_shoe_vector=0x101b302e8
itemdef_shield_vector=0x101b30300
itemdef_helm_vector=0x101b30318
itemdef_pant_vector=0x101b30330
itemdef_food_vector=0x101b30348
language_vector=0x101b30378
translation_vector=0x101b303a8
colors_vector=0x101b38f40
shapes_vector=0x101b38f58
reactions_vector=0x101b38f88
base_materials=0x101b39b18
all_syndromes_vector=0x101b3aff8
events_vector=0x101b3b5d8
historical_figures_vector=0x101b3b608
world_site_type=0x0050
active_sites_vector=0x00048360
[offsets]
word_table=0x0038
string_buffer_offset=0x0000
[word_offsets]
base=0x0000
noun_singular=0x0008
noun_plural=0x0010
adjective=0x0018
verb=0x0028
present_simple_verb=0x0030
past_simple_verb=0x0038
past_participle_verb=0x0040
present_participle_verb=0x0048
words=0x0010
word_type=0x002c
language_id=0x003c
[general_ref_offsets]
ref_type=0x0008
artifact_id=0x0008
item_id=0x0008
[race_offsets]
name_singular=0x0008
name_plural=0x0010
adjective=0x0018
baby_name_singular=0x0020
baby_name_plural=0x0028
child_name_singular=0x0030
child_name_plural=0x0038
pref_string_vector=0x0070
castes_vector=0x00a0
pop_ratio_vector=0x00b8
materials_vector=0x2228
flags=0x00d0
tissues_vector=0x2240
[caste_offsets]
caste_name=0x0008
caste_descr=0x0088
caste_trait_ranges=0x0234
caste_phys_att_ranges=0x0de8
baby_age=0x0178
child_age=0x017c
adult_size=0x0190
flags=0x0360
body_info=0x0378
skill_rates=0x0578
caste_att_rates=0x0ffc
caste_att_caps=0x112c
shearable_tissues_vector=0x12b8
extracts=0x1c08
[hist_entity_offsets]
histfigs=0x0098
beliefs=0x0cc8
squads=0x1150
positions=0x1048
assignments=0x1098
assign_hist_id=0x0004
assign_position_id=0x000c
position_id=0x0008
position_name=0x0080
position_female_name=0x0090
position_male_name=0x00a0
[hist_figure_offsets]
hist_race=0x0002
hist_name=0x0038
id=0x00a8
hist_fig_info=0x00f8
reputation=0x0058
current_ident=0x0030
fake_name=0x0008
fake_birth_year=0x0060
fake_birth_time=0x0064
kills=0x0030
killed_race_vector=0x0018
killed_undead_vector=0x0090
killed_counts_vector=0x00a8
[hist_event_offsets]
event_year=0x0008
id=0x0020
killed_hist_id=0x0024
[item_offsets]
item_type=0x0004
item_def=0x00e0
id=0x001c
general_refs=0x0038
stack_size=0x0078
wear=0x009c
mat_type=0x00ac
mat_index=0x00b0
maker_race=0x00b4
quality=0x00b6
[item_subtype_offsets]
sub_type=0x0010
name=0x0048
name_plural=0x0050
adjective=0x0058
[item_filter_offsets]
item_subtype=0x0002
mat_class=0x0004
mat_type=0x0006
mat_index=0x0008
[weapon_subtype_offsets]
single_size=0x0078
multi_size=0x007c
ammo=0x0070
melee_skill=0x0068
ranged_skill=0x006a
[armor_subtype_offsets]
layer=0x0010
mat_name=0x0060
other_armor_level=0x0064
armor_adjective=0x0068
armor_level=0x0074
chest_armor_properties=0x0080
pants_armor_properties=0x0090
other_armor_properties=0x0080
[material_offsets]
solid_name=0x0058
liquid_name=0x0060
gas_name=0x0068
powder_name=0x0070
paste_name=0x0078
pressed_name=0x0080
flags=0x0110
inorganic_materials_vector=0x0190
inorganic_flags=0x0020
[plant_offsets]
name=0x0038
name_plural=0x0040
name_leaf_plural=0x0068
name_seed_plural=0x0058
materials_vector=0x0190
flags=0x0028
[descriptor_offsets]
color_name=0x0038
shape_name_plural=0x0040
[health_offsets]
parent_id=0x0010
body_part_flags=0x0018
layers_vector=0x0028
number=0x0054
names_vector=0x0060
names_plural_vector=0x0078
layer_tissue=0x0008
layer_global_id=0x0050
tissue_name=0x0018
tissue_flags=0x0008
[dwarf_offsets]
first_name=0x0000
nick_name=0x0008
last_name=0x0010
custom_profession=0x0048
profession=0x0050
race=0x0054
flags1=0x00c0
flags2=0x00c4
flags3=0x00c8
meeting=0x00d0
caste=0x00dc
sex=0x00de
id=0x00e0
animal_type=0x00e8
civ=0x00f0
specific_refs=0x0158
squad_id=0x0188
squad_position=0x018c
recheck_equipment=0x0218
mood=0x02f8
birth_year=0x0324
birth_time=0x0328
pet_owner_id=0x0354
current_job=0x0468
physical_attrs=0x0594
body_size=0x0678
size_info=0x063c
curse=0x07d0
curse_add_flags1=0x07bc
turn_count=0x0888
souls=0x0998
states=0x08f0
labors=0x09d0
hist_id=0x0af8
artifact_name=0x0950
active_syndrome_vector=0x0b68
syn_sick_flag=0x004c
unit_health_info=0x0c10
temp_mood=0x07a8
counters1=0x0790
counters2=0x07ac
counters3=0x08c0
limb_counters=0x0b00
blood=0x0654
body_component_info=0x0480
layer_status_vector=0x0048
wounds_vector=0x0540
mood_skill=0x0470
used_items_vector=0x0c18
affection_level=0x000c
inventory=0x03a8
inventory_item_mode=0x0008
inventory_item_bodypart=0x000a
[syndrome_offsets]
cie_effects=0x0008
cie_end=0x0018
cie_first_perc=0x0098
cie_phys=0x00b0
cie_ment=0x00cc
syn_classes_vector=0x00b0
trans_race_id=0x00b0
[unit_wound_offsets]
parts=0x0008
id=0x0004
layer=0x0006
general_flags=0x002c
flags1=0x0064
flags2=0x0068
effects_vector=0x0048
bleeding=0x006c
pain=0x0070
cur_pen=0x0098
max_pen=0x009a
[soul_details]
name=0x0008
orientation=0x0058
mental_attrs=0x007c
skills=0x01e8
preferences=0x0200
personality=0x0218
beliefs=0x0000
emotions=0x0030
goals=0x0048
goal_realized=0x0028
traits=0x0080
stress_level=0x0120
[emotion_offsets]
emotion_type=0x0000
strength=0x0008
thought_id=0x000c
sub_id=0x0010
level=0x0014
year=0x0020
year_tick=0x0024
[job_details]
id=0x0014
mat_type=0x0030
mat_index=0x0034
mat_category=0x0048
on_break_flag=0x0011
sub_job_id=0x0050
reaction=0x0008
reaction_skill=0x0050
[squad_offsets]
id=0x0000
name=0x0008
alias=0x0050
members=0x0058
orders=0x0070
schedules=0x0088
sched_size=0x0020
sched_orders=0x0010
sched_assign=0x0028
alert=0x00a0
carry_food=0x0170
carry_water=0x0172
ammunition=0x00f8
ammunition_qty=0x000c
quiver=0x0150
backpack=0x0154
flask=0x0158
armor_vector=0x0080
helm_vector=0x0098
pants_vector=0x00b0
gloves_vector=0x00c8
shoes_vector=0x00e0
shield_vector=0x00f8
weapon_vector=0x0110
uniform_item_filter=0x0004
uniform_indiv_choice=0x0030
[activity_offsets]
activity_type=0x0004
events=0x0008
participants=0x0048
sq_lead=0x00b4
sq_skill=0x00bc
sq_train_rounds=0x00c8
pray_deity=0x00b0
pray_sphere=0x00b4
knowledge_category=0x00c0
knowledge_flag=0x00c4
perf_type=0x00b0
perf_participants=0x00e0
perf_histfig=0x000c
[valid_flags_2]
size=0
[invalid_flags_1]
size=9
1\name=a skeleton
1\value=0x00002000
2\name=a merchant
2\value=0x00000040
3\name=outpost liason or diplomat
3\value=0x00000800
4\name=an invader or hostile
4\value=0x00020000
5\name=an invader or hostile
5\value=0x00080000
6\name=resident, invader or ambusher
6\value=0x00600000
7\name=part of a merchant caravan
7\value=0x00000080
8\name="Dead, Jim."
8\value=0x00000002
9\name=marauder
9\value=0x00000010
[invalid_flags_2]
size=5
1\name="killed, Jim."
1\value=0x00000080
2\name=from the Underworld. SPOOKY!
2\value=0x00040000
3\name=resident
3\value=0x00080000
4\name=uninvited visitor
4\value=0x00400000
5\name=visitor
5\value=0x00800000
[invalid_flags_3]
size=1
1\name=a ghost
1\value=0x00001000