libwebsockets编译

x86_64:
(1) cd 到CMakeList.txt所在的目录，创建/build/arch/x86_64的目录
(2) cmake ../../../
需要安装libssl-dev

arm32:
(1) cd 到CMakeList.txt所在的目录，创建/build/arch/arm32的目录
(2) cmake -DCMAKE_INSTALL_PREFIX=/opt/arm-libs/arm32 -DCMAKE_TOOLCHAIN_FILE=arm32.cmake -DLWS_WITHOUT_EXTENSIONS=1 -DLWS_WITH_SSL=0 -DLWS_WITH_ZIP_FOPS=0 -DLWS_WITH_ZLIB=0 ../../../
(3) arm32.cmake的内容如下：

#
# CMake Toolchain file for crosscompiling on ARM.
#
# This can be used when running cmake in the following way:
#  cd build/
#  cmake .. -DCMAKE_TOOLCHAIN_FILE=../cross-arm-linux-gnueabihf.cmake
#

set(CROSS_PATH /usr)

# Target operating system name.
set(CMAKE_SYSTEM_NAME Linux)

# Name of C compiler.
set(CMAKE_C_COMPILER "${CROSS_PATH}/bin/arm-linux-gnueabihf-gcc")
set(CMAKE_CXX_COMPILER "${CROSS_PATH}/bin/arm-linux-gnueabihf-g++")

#
# Different build system distros set release optimization level to different
# things according to their local policy, eg, Fedora is -O2 and Ubuntu is -O3
# here.  Actually the build system's local policy is completely unrelated to
# our desire for cross-build release optimization policy for code built to run
# on a completely different target than the build system itself.
#
# Since this goes last on the compiler commandline we have to override it to a
# sane value for cross-build here.  Notice some gcc versions enable broken
# optimizations with -O3.
#
if (CMAKE_BUILD_TYPE MATCHES RELEASE OR CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES release)
	set(CMAKE_C_FLAGS_RELEASE ${CMAKE_C_FLAGS_RELEASE} -O2)
	set(CMAKE_CXX_FLAGS_RELEASE ${CMAKE_CXX_FLAGS_RELEASE} -O2)
endif()

# Where to look for the target environment. (More paths can be added here)
set(CMAKE_FIND_ROOT_PATH "${CROSS_PATH}")

# Adjust the default behavior of the FIND_XXX() commands:
# search programs in the host environment only.
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)

# Search headers and libraries in the target environment only.
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

arm64:
(1) cd 到CMakeList.txt所在的目录，创建/build/arch/arm64的目录
(2) cmake -DCMAKE_INSTALL_PREFIX=/opt/arm-libs/arm64 -DCMAKE_TOOLCHAIN_FILE=arm64.cmake -DLWS_WITHOUT_EXTENSIONS=1 -DLWS_WITH_SSL=0 -DLWS_WITH_ZIP_FOPS=0 -DLWS_WITH_ZLIB=0 ../../../
(3) arm64.cmake的内容如下：

set(CROSS_PATH /usr)

# Target operating system name.
set(CMAKE_SYSTEM_NAME Linux)

# Name of C compiler.
set(CMAKE_C_COMPILER "${CROSS_PATH}/bin/aarch64-linux-gnu-gcc")
set(CMAKE_CXX_COMPILER "${CROSS_PATH}/bin/aarch64-linux-gnu-g++")