Configure datachannel target_properties for APPLE

After 7591b96 libdatachannel stopped working with OBS on macOS[0].
XCode only resolves one level of symlinks [1]. libdatachannel
is generating two levels.

This commit updates CMake to instead use ELF Headers instead of file
names to communicate version of macOS.

[0] https://stackoverflow.com/questions/29946961/xcode-copy-files-build-phase-and-symlinks
[1] obsproject/obs-deps#204 (comment)

CMakeLists.txt

@@ -257,11 +257,22 @@ add_library(datachannel SHARED
 	${LIBDATACHANNEL_HEADERS}
 	${LIBDATACHANNEL_IMPL_SOURCES}
 	${LIBDATACHANNEL_IMPL_HEADERS})
+
 set_target_properties(datachannel PROPERTIES
 	VERSION ${PROJECT_VERSION}
 	SOVERSION ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
 	CXX_STANDARD 17
 	CXX_VISIBILITY_PRESET default)
+
+if(APPLE)
+	set_target_properties(datachannel PROPERTIES
+		VERSION 0
+		SOVERSION 0
+		MACHO_COMPATIBILITY_VERSION 0
+		MACHO_CURRENT_VERSION ${PROJECT_VERSION}
+		NO_SONAME TRUE)
+endif()
+
 target_compile_definitions(datachannel PRIVATE RTC_EXPORTS)
 
 add_library(datachannel-static STATIC EXCLUDE_FROM_ALL