Include bundled libxsd headers before /usr/local/lib to allow building
with installed devel/xsd.

look for dlopen in libc, not libdl
Index: external/linphone-sdk/liblinphone/CMakeLists.txt
--- external/linphone-sdk/liblinphone/CMakeLists.txt.orig
+++ external/linphone-sdk/liblinphone/CMakeLists.txt
@@ -102,7 +102,7 @@ include(CheckCXXCompilerFlag)
 
 check_symbol_exists(getifaddrs "sys/types.h;ifaddrs.h" HAVE_GETIFADDRS)
 
-check_library_exists("dl" "dlopen" "" HAVE_DLOPEN)
+check_library_exists("c" "dlopen" "" HAVE_DLOPEN)
 
 if(NOT CMAKE_INSTALL_RPATH AND CMAKE_INSTALL_PREFIX)
 	set(CMAKE_INSTALL_RPATH ${CMAKE_INSTALL_FULL_LIBDIR})
@@ -263,6 +263,7 @@ include_directories(
 	coreapi
 	include
 	src
+	${LIBXSD_INCLUDE_DIRS}
 	${CMAKE_CURRENT_BINARY_DIR}
 	${CMAKE_CURRENT_BINARY_DIR}/coreapi/
 )
