Compile iOS dynamic library(.framework) with cmake - c++

Question

I've compiled a c++ dynamic library using cmake and I want to add to my iOS app. But the header file directory of this .framework is empty, I refer to the CMakeFiles written in the cmake documentation. I don't know where the problem is?
Any help would be greatly appreciated.
Here is my CMake script
cmake_minimum_required(VERSION 3.2)
project(Xml C CXX)
set(CMAKE_SYSTEM_NAME Darwin)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(HEADERS
./include
)
include_directories(
${HEADERS}
)
aux_source_directory(. DIR_SRCS)
add_library(Xml SHARED
${DIR_SRCS}
${HEADERS}
)
set_target_properties(Xml PROPERTIES
FRAMEWORK TRUE
FRAMEWORK_VERSION CXX
PUBLIC_HEADER ${HEADERS}
XCODE_ATTRIBUTE_CODE_SIGN_IDENTITY "iPhone Developer"
)
Compilation progress
Scanning dependencies of target Xml
[ 10%] Building CXX object CMakeFiles/Xml.dir/ILock.cpp.o
[ 20%] Building CXX object CMakeFiles/Xml.dir/ParamSet.cpp.o
[ 30%] Building CXX object CMakeFiles/Xml.dir/StringConvert.cpp.o
[ 40%] Building CXX object CMakeFiles/Xml.dir/XmlFile.cpp.o
[ 50%] Building CXX object CMakeFiles/Xml.dir/XmlInterface.cpp.o
[ 60%] Building CXX object CMakeFiles/Xml.dir/tinystr.cpp.o
[ 70%] Building CXX object CMakeFiles/Xml.dir/tinyxml.cpp.o
[ 80%] Building CXX object CMakeFiles/Xml.dir/tinyxmlerror.cpp.o
[ 90%] Building CXX object CMakeFiles/Xml.dir/tinyxmlparser.cpp.o
[100%] Linking CXX shared library Xml.framework/Xml
Copying OS X content Xml.framework/Versions/CXX/Headers/include
[100%] Built target Xml
Compiled dynamic library

Answer 1

The issue is solved. CMake can't get all header files with the ./include syntax. The following is a modified CMake script.
set(HEADERS
./include/a.h
./include/b.h
./include/c.h
)
include_directories(
./include
)
aux_source_directory(. DIR_SRCS)
add_library(Xml SHARED
${DIR_SRCS}
${HEADERS}
)
set_target_properties(Xml PROPERTIES
FRAMEWORK TRUE
PUBLIC_HEADER "${HEADERS}"
)