Cross-compiling for iOS fails at libwebsocket step

[mehmetcy84]

I am using the latest master code to build the Kinesis C SDK for iOS arm64. I know there is a Kinesis iOS SDK, but I need to build the Kinesis C SDK for the WebRTC Stack. (I still use the Kinesis iOS SDK for the signalling)

I configured an iOS toolchain I got from here:
https://github.com/leetal/ios-cmake
And I use this command under:
/Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/build
folder to build the Kinesis SDK:
cmake .. -G Xcode -DCMAKE_TOOLCHAIN_FILE=../ios.toolchain.cmake -DPLATFORM=OS64 -DCMAKE_XCODE_ATTRIBUTE_DEVELOPMENT_TEAM=[PRIVATE] -DPRODUCT_BUNDLE_IDENTIFIER=[PRIVATE] ..

I enabled mbedtls (disabled OpenSSL). The mbedtls libraries are built fine (I checked them with lipo and they are of type arm64) but during libwebsocket build, I get the following error:

In file included from /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/core/private-lib-core.h:144:
/Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/include/libwebsockets.h:287:10: fatal error: 'mbedtls/ssl.h' file not found
#include <mbedtls/ssl.h>

But when I check:
/Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/include/mbedtls/ssl.h
I can find the header there. So what might be the cause of the failure? And how can I remedy this?

These are the changes I made in CMakeLists.txt

set(CMAKE_SYSTEM_NAME iOS)
set(CMAKE_OSX_SYSROOT iphoneos)
set(CMAKE_XCODE_ATTRIBUTE_DEVELOPMENT_TEAM [PRIVATE])
set(PRODUCT_BUNDLE_IDENTIFIER [PRIVATE])

In libwebsockets-CMakeLists.txt

        -DCMAKE_SYSTEM_NAME=iOS
        -DCMAKE_OSX_SYSROOT=iphoneos
        -DCMAKE_XCODE_ATTRIBUTE_DEVELOPMENT_TEAM=[PRIVATE]

A broader section of the error in the terminal:

In file included from /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/plat/unix/unix-service.c:28:
In file included from /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/core/private-lib-core.h:144:
/Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/include/libwebsockets.h:287:10: fatal error: 'mbedtls/ssl.h' file not found
#include <mbedtls/ssl.h>
^~~~~~~~~~~~~~~
1 error generated.
** BUILD FAILED **
The following build commands failed:
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/tls.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/tls/tls.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/tls-sessions.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/tls/tls-sessions.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/wsi.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/core-net/wsi.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/wsi-timeout.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/core-net/wsi-timeout.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/vhost.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/core-net/vhost.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/vfs.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/core/vfs.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/unix-sockets.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/plat/unix/unix-sockets.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
CompileC /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets-build/build/websockets.build/Debug-iphoneos/Objects-normal/arm64/unix-service.o /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/src/project_libwebsockets/lib/plat/unix/unix-service.c normal arm64 c com.apple.compilers.llvm.clang.1_0.compiler (in target 'websockets' from project 'libwebsockets')
(8 failures)
Command PhaseScriptExecution failed with a nonzero exit code
** BUILD FAILED **
The following build commands failed:
PhaseScriptExecution Generate\ build/src/project_libwebsockets-stamp/$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)/project_libwebsockets-build /Users/mehmet/Documents/amazon-kinesis-video-streams-webrtc-sdk-c/open-source/libwebsockets/build/libwebsocket-download.build/Debug/project_libwebsockets.build/Script-3544212B547275A98E8224ED.sh (in target 'project_libwebsockets' from project 'libwebsocket-download')
(1 failure)
CMake Error at CMake/Utilities.cmake:75 (message):
CMake step for libwebsockets failed: 65
Call Stack (most recent call first):
CMakeLists.txt:198 (build_dependency)
-- Configuring incomplete, errors occurred!