Intermediate static libs have issues.

Switch back to including the bundled expat sources directly in the
targets, since transitive linking of static libs is very awkward.
Makes static build happy again (let's see what else breaks)

3rdparty/expat/CMakeLists.txt

@@ -1,11 +1,9 @@
 
-
 configure_file (
     "${PROJECT_SOURCE_DIR}/3rdparty/expat/expat_config_cmake.in"
     "${PROJECT_BINARY_DIR}/3rdparty/expat/expat_config.h"
 )
 
-
 set(expat_sources 
 	asciitab.h
         hashtable.h
@@ -28,15 +26,8 @@ set(expat_sources
         sg_expat_external.h 
 	)
 
-
-# this code will be linked into SimGearCore shared object, so it 
-# must be compiled with -fPIC too
-
-
-if(SIMGEAR_SHARED AND UNIX)
-	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC")
-endif()
-
-add_library(local_expat STATIC ${expat_sources})
-
+foreach(s ${expat_sources})
+	set_property(GLOBAL
+		APPEND PROPERTY LOCAL_EXPAT_SOURCES 
+        "${CMAKE_CURRENT_SOURCE_DIR}/${s}")
+endforeach()