please help with me to cherry-pick LDC IOS arch and target support.

[Newbie2019]

https://github.com/ldc-developers/ldc/issues/1081

Is any one can suggestion the working step?

the ldc source code change too much, I dont know how to fix all 
this errors.

here is a commit list by Dan Olson from 
https://github.com/smolt/ldc/commits/ios:

a0201e4c - Dan Olson - 2017-01-22 08:45:28 -0800 - Update phobos 
submodule
1df9b441 - Dan Olson - 2017-01-22 08:35:18 -0800 - Disable  fake 
bitcode generation
d7dbcd48 - Dan Olson - 2017-01-22 08:32:32 -0800 - Support cmake 
3.7.1
ef9ba25c - Dan Olson - 2017-01-22 08:22:41 -0800 - Make iOS arm 
abi use byval alignment
73d96121 - Dan Olson - 2017-01-21 18:12:50 -0800 - Fix iOS arm abi
4c8053fc - Dan Olson - 2017-01-21 15:08:49 -0800 - Fix iOS arm64 
abi, remove byval attribute use
deb3847f - Dan Olson - 2016-04-19 05:16:38 +0000 - ARM AAPCS: 
struct rewrite with 8-byte alignment
7b7d9adb - Dan Olson - 2016-04-17 10:45:36 -0700 - dmd-testsuite 
with ARM happy constfold
ae99d9c7 - Dan Olson - 2016-03-07 16:59:13 +0000 - Support ARM 
AAPCS style va_list for C++ mangling
7cba1a45 - Dan Olson - 2016-02-25 19:52:23 +0000 - Fix non-x86 
__traits compiles for dmd inline asm
51074b0c - Dan Olson - 2016-02-25 19:29:14 +0000 - Zero extend 
char and wchar
ad1bb14b - Dan Olson - 2016-02-25 19:17:02 +0000 - ARM: 
Re-reverse parameter order for extern(D)
9751f3f2 - Dan Olson - 2016-02-25 19:11:41 +0000 - ARM: Use byval 
attr for types > 64-bytes
13cef8a9 - Dan Olson - 2016-02-06 01:22:01 -0800 - Override LLVM 
default relocation model for ARM
b9b4564d - Dan Olson - 2016-02-05 09:04:09 -0800 - Implement ARM 
AAPCS ABI
0b63c58a - Dan Olson - 2016-01-20 22:22:47 -0800 - cmake: Detect 
if llvm assertions enabled
f4125943 - Dan Olson - 2016-01-17 12:26:02 -0800 - Update 
druntime with ldc-developers/druntime#53
963a5f4c - Dan Olson - 2016-01-09 13:57:10 -0800 - Create empty 
embedded bitcode sections
818d760f - Dan Olson - 2016-01-06 21:06:30 -0800 - Update 
druntime with ldc-developers/druntime#51
14c06436 - Dan Olson - 2015-12-23 12:46:35 -0800 - Re-enable 
core.internal.convert unit tests
a77354b3 - Dan Olson - 2015-12-20 23:53:55 -0800 - Update phobos 
submodule
5db1db9c - Dan Olson - 2015-12-20 23:34:29 -0800 - Update 
druntime submodule
68ebcbbb - Dan Olson - 2015-12-20 17:33:13 -0800 - WIP - WatchOS 
exceptions need frame pointer
153a6232 - Dan Olson - 2015-12-20 17:23:37 -0800 - Initial 
support for TVOS and WatchOS
bb378f7c - Dan Olson - 2015-12-16 00:03:05 -0800 - Define 
HAVE_UNISTD_H for zlib
dafbfb29 - Dan Olson - 2015-12-02 07:15:51 -0800 - Make versions 
OSX and iOS exclusive
49ba2910 - Dan Olson - 2015-11-12 10:52:05 -0800 - OS X - default 
OS to macosx instead of darwin
6df2b997 - Dan Olson - 2015-11-07 22:55:45 -0800 - clang-format 
iOS changes
f1e18acd - Dan Olson - 2015-11-07 16:59:59 -0800 - Update phobos 
submodule with fixed unittests
1d66334b - Dan Olson - 2015-11-03 08:46:37 -0800 - Start using 
term iOS instead of iPhone OS
3a8e467b - Dan Olson - 2015-10-30 23:02:39 -0700 - Cleanup
f6bc885d - Dan Olson - 2015-10-30 22:38:57 -0700 - iOS arm64 - 
avoid float vararg promotion
94debcc8 - Dan Olson - 2015-10-21 21:12:16 -0700 - Add versions 
iOS and Darwin
0826f926 - Dan Olson - 2015-10-21 20:30:54 -0700 - iOS ARM - 
extern(C) non-POD struct returns
dfae2e09 - Dan Olson - 2015-10-21 19:21:19 -0700 - OS X x86 - 
extern(C) non-POD struct returns
3182b05a - Dan Olson - 2015-10-04 23:30:07 -0700 - iOS arm64 - 
complete HFA arg/return value rewrite
9b328d16 - Dan Olson - 2015-09-30 21:26:14 -0700 - iOS arm64 - 
rewrite HFA arg, rewrite variadic args
2091e237 - Dan Olson - 2015-09-30 21:22:41 -0700 - iOS ARM - also 
rewrite variadic args
698689e0 - Dan Olson - 2015-09-27 09:38:11 -0700 - iOS arm64 - C 
ABI struct and HFA rewrites
45f53d1e - Dan Olson - 2015-09-18 09:42:21 -0700 - Update 
druntime/phobos submodules
5d6acfbc - Dan Olson - 2015-09-15 08:13:43 -0700 - iOS ARM - 
workaround unaligned load of sarray
d7059476 - Dan Olson - 2015-09-14 09:27:05 -0700 - iOS arm64 - 
add druntime/phobos support
741bf9be - Dan Olson - 2015-09-14 00:37:34 -0700 - Remove unused 
method in abi-aarch64
81834cb7 - Dan Olson - 2015-09-14 00:35:27 -0700 - Add missing 
arg to _d_arraycatnT declaration
3ff30190 - Dan Olson - 2015-09-14 00:31:47 -0700 - Some file 
reorg of iOS ABI files - part2
fdc11a64 - Dan Olson - 2015-09-14 00:29:55 -0700 - Some file 
reorg of iOS ABI files
5aa8ccf7 - Dan Olson - 2015-09-14 00:27:06 -0700 - iOS arm64 ABI 
added
dcb95be0 - Dan Olson - 2015-09-07 12:41:14 -0700 - iOS - Update 
for callingConv change
0bcb802a - Dan Olson - 2015-09-07 10:07:58 -0700 - OS X x86 ABI - 
fix struct return
f19b1a95 - Dan Olson - 2015-09-07 10:06:11 -0700 - OS X - Fix 
MULTILIB test_runner linking
f713ee56 - Dan Olson - 2015-08-29 11:56:00 -0700 - OS X x86 ABI - 
fix struct return
2488032b - Dan Olson - 2015-07-30 09:50:33 -0700 - iOS ARM - 
Follow C ABI for passing structs
e6a98c5a - Dan Olson - 2015-07-27 22:15:55 -0700 - iOS ARM - 
Follow ABI for integer-like struct return
542768cd - Dan Olson - 2015-07-24 23:59:38 -0700 - cmake 
-DWITH_CURL to include curl modules in phobos
3a90a2c3 - Dan Olson - 2015-07-23 01:05:32 -0700 - Update 
druntime submodule
549f5d04 - Dan Olson - 2015-07-23 00:30:21 -0700 - Build unittest 
for each iOS arch, remove curl
8d2982a9 - Dan Olson - 2015-07-20 23:49:35 -0700 - Match new 
TargetABI callingConv()
1acd6a1c - Dan Olson - 2015-07-19 16:58:20 -0700 - Update 
druntime/phobos with unittest fixes
30fbaa6d - Dan Olson - 2015-07-16 22:16:36 -0700 - WIP MacOSX - 
dead_strip experiment
358d9b6e - Dan Olson - 2015-07-16 21:45:37 -0700 - WIP build 
unittests foreach  IPHONEOS_ARCH
81a43968 - Dan Olson - 2015-07-16 21:44:57 -0700 - WIP iOS arm64
96bf3d38 - Dan Olson - 2015-07-07 00:26:35 -0700 - iOS - update 
druntime to avoid dyld private APIs
7a0b7709 - Dan Olson - 2015-07-05 18:35:19 -0700 - iOS - add 
armv7s architecture
be94f966 - Dan Olson - 2015-07-04 11:31:24 -0700 - Update 
druntime/phobos submodules for iOS Sim
730be86d - Dan Olson - 2015-07-04 11:27:55 -0700 - iOS - 
preliminary universal lib support
3670da74 - Dan Olson - 2015-07-04 10:11:16 -0700 - ARM - consider 
thumb too for default cpu
08fafa20 - Dan Olson - 2015-07-04 10:02:45 -0700 - iOS - Disable 
neon when optimizing
6496aeb2 - Dan Olson - 2015-07-04 09:59:02 -0700 - iOS Simulator 
- iOS default relocation is PIC
36d514c9 - Dan Olson - 2015-06-21 23:49:40 -0700 - Update 
druntime and phobos submodules
98109d9e - Dan Olson - 2015-06-02 16:34:35 -0700 - Cross compile 
from OSX to target's real type
1878e43c - Dan Olson - 2015-05-30 08:40:40 -0700 - Support 
i386-apple-ios (IPhoneSimulator)
1bd2fbcb - Dan Olson - 2015-05-15 23:26:18 -0700 - Change iOS 
extern(D) ABI from fastcc to ccc
3e535bd8 - Dan Olson - 2015-05-15 23:25:12 -0700 - Fix type-oh in 
help string
d25cec11 - Dan Olson - 2015-05-15 23:25:12 -0700 - Work toward 
getting the iOS ABI correct
1c2cf940 - Dan Olson - 2015-05-15 23:25:12 -0700 - ABI for iOS 
that passes structs as values
b034a111 - Dan Olson - 2015-05-15 23:20:39 -0700 - Add version 
IPhoneOS
5a57557e - Dan Olson - 2015-05-15 23:17:01 -0700 - real == double 
conditional on USE_REAL64
92e24ff1 - Dan Olson - 2015-05-15 23:17:00 -0700 - Fix -vtls help 
string
2965d94b - Dan Olson - 2015-05-15 23:15:41 -0700 - Implement 
-vtls in ldc
922a80f9 - Dan Olson - 2015-05-15 23:10:10 -0700 - new option 
-disable-tls
ef096bb8 - Dan Olson - 2015-05-15 22:59:45 -0700 - switch 
submodule phobos to smolt fork for iOS and update to latest 
druntime
5d8b35ed - Dan Olson - 2015-05-15 22:58:07 -0700 - switch 
submodule druntime to smolt fork for ios
85569bfb - Dan Olson - 2015-05-15 22:58:07 -0700 - Hard code in 
so real == double.  This is an issue when cross compiling since 
dmd uses the host C libs to determine the properties of type 
real.  This change breaks ldc for native compiles, will have to 
come up with better solution.
3c4c4410 - Dan Olson - 2015-05-15 22:58:07 -0700 - Some useful 
notes in comments
e2bcfacc - Dan Olson - 2015-05-15 22:51:45 -0700 - cmake 
TARGET_C_FLAGS added for building target libraries
a7f5ed8a - Dan Olson - 2015-05-15 22:48:44 -0700 - allow ios as 
triple OS
dfbb6cdd - Dan Olson - 2015-05-15 22:48:44 -0700 - disable TLS 
for now
9db58c39 - Dan Olson - 2015-05-15 22:48:44 -0700 - work with 
libc++
08d92ede - Dan Olson - 2015-04-27 00:13:11 -0700 - Update to 
ldc-developers/dmd-testsuite#9
ca2814f0 - Dan Olson - 2015-04-06 22:04:15 -0700 - Update to 
ldc-developers/phobos#15
1c9329de - Dan Olson - 2015-04-05 23:53:20 -0700 - Add new dmd 
-verrors option
8246071a - Dan Olson - 2015-03-29 15:48:55 -0700 - index on 
ios-merge-2.067: b266d23 Merge branch 'merge-2.067' into 
ios-merge-2.067
17c99659 - Dan Olson - 2015-03-28 11:44:26 -0700 - Use old 
builtinTypeInfo logic for type class
1d054009 - Dan Olson - 2015-03-22 22:30:13 -0700 - Add new phobos 
subdirs
a0e7ebfc - Dan Olson - 2015-03-22 22:22:29 -0700 - Add new phobos 
subdirs
d2f49bc3 - Dan Olson - 2015-03-22 16:44:12 -0700 - Change iOS 
extern(D) ABI from fastcc to ccc
b2d51d65 - Dan Olson - 2015-03-21 18:25:20 +0100 - Fix cmake bug 
when ldc is a submodule
73df563a - Dan Olson - 2015-03-09 00:13:54 -0700 - Fix cmake bug 
when ldc is a submodule
af9d1a8c - Dan Olson - 2015-03-09 00:11:05 -0700 - Update 
druntime submodule
0be5ead4 - Dan Olson - 2015-03-09 00:11:05 -0700 - Fix cmake bug 
when ldc is a submodule
ecd68430 - Dan Olson - 2015-03-01 00:29:32 -0800 - Stray tab 
cleanup
f554c322 - Dan Olson - 2015-02-28 23:57:38 -0800 - Lookup default 
float-abi for thumb same as arm
3c9da62e - Dan Olson - 2015-02-28 23:53:30 -0800 - Set version 
ARM_SoftFP
b5b7e287 - Dan Olson - 2015-02-10 19:06:32 -0800 - Update 
submodules with latest changes
6e7c9cd5 - Dan Olson - 2015-02-10 19:05:58 -0800 - Fix type-oh in 
help string
e0cf8e85 - Dan Olson - 2015-02-10 19:03:30 -0800 - Lookup default 
float-abi for thumb same as arm
cd3a8c00 - Dan Olson - 2015-02-10 19:02:37 -0800 - Work toward 
getting the iOS ABI correct
2bc41698 - Dan Olson - 2015-02-10 18:56:37 -0800 - ABI for iOS 
that passes structs as values
526692e9 - Dan Olson - 2015-02-04 15:50:20 -0800 - Add version 
IPhoneOS
5a19080e - Dan Olson - 2015-01-28 00:38:02 -0800 - Set version 
ARM_SoftFP
2f273bdc - Dan Olson - 2015-01-23 08:21:43 -0800 - real == double 
conditional on USE_REAL64
40a2e7c6 - Dan Olson - 2015-01-15 07:54:41 -0800 - Fix -vtls help 
string
c3167169 - Dan Olson - 2015-01-12 08:17:10 -0800 - Update phobos 
submodule to ios-release-0.15.0 tag
7a611545 - Dan Olson - 2015-01-04 19:51:43 -0800 - Update 
druntime and phobos submodules commits
8b0bd382 - Dan Olson - 2015-01-02 12:18:36 -0800 - Implement 
-vtls in ldc
762c01d9 - Dan Olson - 2015-01-02 12:09:03 -0800 - new option 
-disable-tls
c66fbbe0 - Dan Olson - 2014-05-04 21:39:34 -0700 - When calling a 
C variadic (...), pass structs by value instead of reference.  
This will match with C calling convention.
54d2f3f2 - Dan Olson - 2014-03-27 01:05:47 -0700 - switch 
submodule phobos to smolt fork for iOS and update to latest 
druntime
872d0674 - Dan Olson - 2014-02-21 00:54:28 -0800 - update 
druntime with work exception handling for iOS
06b2b1f9 - Dan Olson - 2014-02-12 20:04:26 -0800 - switch 
submodule druntime to smolt fork for ios
ed74a7c9 - Dan Olson - 2014-02-12 08:07:01 -0800 - Hard code in 
so real == double.  This is an issue when cross compiling since 
dmd uses the host C libs to determine the properties of type 
real.  This change breaks ldc for native compiles, will have to 
come up with better solution.
48772743 - Dan Olson - 2014-02-09 13:49:04 -0800 - Some useful 
notes in comments
552f31c8 - Dan Olson - 2014-02-03 22:42:21 -0800 - switch 
druntime to ios dev branch
4447c660 - Dan Olson - 2014-02-02 00:18:47 -0800 - cmake 
TARGET_C_FLAGS added for building target libraries
e2b53f47 - Dan Olson - 2014-02-02 00:16:31 -0800 - allow ios as 
triple OS
d41097bf - Dan Olson - 2014-02-02 00:15:06 -0800 - disable TLS 
for now
591b0bbc - Dan Olson - 2014-02-02 00:13:54 -0800 - work with 
libc++


please do suggestion.