obs-studio/cmake/Modules/FindJansson.cmake

# Once done these will be defined:
#
#  JANSSON_FOUND
#  JANSSON_INCLUDE_DIRS
#  JANSSON_LIBRARIES
#  JANSSON_VERSION

find_package(PkgConfig QUIET)
if (PKG_CONFIG_FOUND)
	pkg_check_modules(_JANSSON QUIET jansson)
endif()

if(CMAKE_SIZEOF_VOID_P EQUAL 8)
	set(_lib_suffix 64)
else()
	set(_lib_suffix 32)
endif()

find_path(Jansson_INCLUDE_DIR
	NAMES jansson.h
	HINTS
		ENV JanssonPath${_lib_suffix}
		ENV JanssonPath
		${_JANSSON_INCLUDE_DIRS}
	PATHS
		/usr/include /usr/local/include /opt/local/include /sw/include)

find_library(Jansson_LIB
	NAMES ${_JANSSON_LIBRARIES} jansson libjansson
	HINTS
		ENV JanssonPath${_lib_suffix}
		ENV JanssonPath
		${_JANSSON_LIBRARY_DIRS}
	PATHS
		/usr/lib /usr/local/lib /opt/local/lib /sw/lib
	PATH_SUFFIXES
		lib${_lib_suffix} lib
		libs${_lib_suffix} libs
		bin${_lib_suffix} bin
		../lib${_lib_suffix} ../lib
		../libs${_lib_suffix} ../libs
		../bin${_lib_suffix} ../bin)

if(JANSSON_VERSION)
	set(_JANSSON_VERSION_STRING "${JANSSON_VERSION}")
elseif(_JANSSON_FOUND AND _JANSSON_VERSION)
	set(_JANSSON_VERSION_STRING "${_JANSSON_VERSION}")
elseif(EXISTS "${Jansson_INCLUDE_DIR}/jansson.h")
	file(STRINGS "${Jansson_INCLUDE_DIR}/jansson.h" _jansson_version_parse
		REGEX "#define[ \t]+JANSSON_VERSION[ \t]+.+")
	string(REGEX REPLACE
		".*#define[ \t]+JANSSON_VERSION[ \t]+\"(.+)\".*" "\\1"
		_JANSSON_VERSION_STRING "${_jansson_version_parse}")
else()
	if(NOT Jansson_FIND_QUIETLY)
		message(WARNING "Failed to find Jansson version")
	endif()
	set(_JANSSON_VERSION_STRING "unknown")
endif()

include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Jansson
	FOUND_VAR JANSSON_FOUND
	REQUIRED_VARS Jansson_LIB Jansson_INCLUDE_DIR
	VERSION_VAR _JANSSON_VERSION_STRING)
mark_as_advanced(Jansson_INCLUDE_DIR Jansson_LIB)

if(JANSSON_FOUND)
	set(JANSSON_INCLUDE_DIRS ${Jansson_INCLUDE_DIR})
	set(JANSSON_LIBRARIES ${Jansson_LIB})
	set(JANSSON_VERSION ${_JANSSON_VERSION_STRING})
endif()