Make datachannel target comply with BUILD_SHARED_LIBS option

Author: paullouisageneau

CMakeLists.txt

@@ -7,6 +7,7 @@ set(PROJECT_DESCRIPTION "C/C++ WebRTC network library featuring Data Channels, M
 include(GNUInstallDirs)
 
 # Options
+option(BUILD_SHARED_LIBS "Build shared libraries" ON)
 option(USE_GNUTLS "Use GnuTLS instead of OpenSSL" OFF)
 option(USE_MBEDTLS "Use Mbed TLS instead of OpenSSL" OFF)
 option(USE_NICE "Use libnice instead of libjuice" OFF)
@@ -49,7 +50,6 @@ endif()
 
 list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake/Modules)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
-set(BUILD_SHARED_LIBS OFF) # to force usrsctp to be built static
 
 if(WIN32)
 	add_definitions(-DWIN32_LEAN_AND_MEAN)
@@ -268,7 +268,7 @@ if(RTC_UPDATE_VERSION_HEADER)
 	)
 endif()
 
-add_library(datachannel SHARED
+add_library(datachannel
 	${LIBDATACHANNEL_SOURCES}
 	${LIBDATACHANNEL_HEADERS}
 	${LIBDATACHANNEL_IMPL_SOURCES}