Fixes the build process when SYSTEM_EXPAT is set to ON.

The problem did not arise on Travis CI because SYSTEM_EXPAT=ON was tested simultaneously with BUILD_SHARED_LIBS=ON.

CMakeLists.txt

@@ -28,12 +28,15 @@ function(get_tail INPUT_STRING OUTPUT_STRING SEPARATOR)
   set(${OUTPUT_STRING} ${TAIL} PARENT_SCOPE)
 endfunction()
 
+find_package(PkgConfig)
+
 ################################################################################
 # Build JSBSim libs and exec                                                   #
 ################################################################################
 
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 add_subdirectory(src)
+get_target_property(libJSBSim_LINK_LIBRARIES libJSBSim LINK_LIBRARIES)
 
 ################################################################################
 # Documentation                                                                #
@@ -90,9 +93,12 @@ endif(CXXTEST_FOUND)
 # Packaging                                                                    #
 ################################################################################
 
-find_package(PkgConfig)
-
 if (PKG_CONFIG_FOUND)
+  if (NOT BUILD_SHARED_LIBS)
+    foreach(_LIB ${libJSBSim_LINK_LIBRARIES})
+      set(JSBSIM_PKG_CONFIG_LINK_LIBRARIES "${JSBSIM_PKG_CONFIG_LINK_LIBRARIES} -l${_LIB}")
+    endforeach(_LIB)
+  endif(NOT BUILD_SHARED_LIBS)
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/JSBSim.pc.in ${CMAKE_CURRENT_BINARY_DIR}/JSBSim.pc @ONLY)
   install(FILES ${CMAKE_CURRENT_BINARY_DIR}/JSBSim.pc DESTINATION lib${LIB_SUFFIX}/pkgconfig COMPONENT devel)
 endif()
@@ -176,6 +182,9 @@ set(CPACK_DEBIAN_RUNTIME_FILE_NAME "${CMAKE_PROJECT_NAME}${EXTENSION_NAME}.deb")
 set(CPACK_DEBIAN_DEVEL_FILE_NAME "${CMAKE_PROJECT_NAME}-devel${EXTENSION_NAME}.deb")
 set(CPACK_DEBIAN_PYMODULES_PACKAGE_NAME "python${PYTHON_VERSION_MAJOR}-${CPACK_PACKAGE_NAME}")
 set(CPACK_DEBIAN_PYMODULES_FILE_NAME "python${PYTHON_VERSION_MAJOR}-${CMAKE_PROJECT_NAME}${EXTENSION_NAME}.deb")
+if (SYSTEM_EXPAT)
+  set(CPACK_DEBIAN_RUNTIME_PACKAGE_DEPENDS "libexpat1")
+endif(SYSTEM_EXPAT)
 if(BUILD_SHARED_LIBS)
   set(CPACK_DEBIAN_DEVEL_PACKAGE_DEPENDS "${CPACK_DEBIAN_RUNTIME_PACKAGE_NAME} (>=${CPACK_PACKAGE_VERSION})")
   set(CPACK_DEBIAN_PYMODULES_PACKAGE_DEPENDS "${CPACK_DEBIAN_RUNTIME_PACKAGE_NAME} (>=${CPACK_PACKAGE_VERSION})")

JSBSim.pc.in

@@ -5,5 +5,5 @@ includedir=@CMAKE_INSTALL_PREFIX@/include
 Name: JSBSim
 Description: An open source flight dynamics & control software library
 Version: @PROJECT_VERSION@
-Libs: -L${libdir} -lJSBSim
+Libs: -L${libdir} -lJSBSim@JSBSIM_PKG_CONFIG_LINK_LIBRARIES@
 Cflags: -I${includedir}/JSBSim

python/CMakeLists.txt

@@ -42,7 +42,6 @@ endif(MSVC)
 cmake_policy(SET CMP0051 NEW)
 get_target_property(libJSBSim_SOURCE_FILES libJSBSim SOURCES)
 get_target_property(libJSBSim_DIRECTORY libJSBSim TARGET_DIRECTORY)
-get_target_property(libJSBSim_LINK_LIBRARIES libJSBSim LINK_LIBRARIES)
 get_directory_property(FLAGS_LIST DIRECTORY ${libJSBSim_DIRECTORY} COMPILE_DEFINITIONS)
 file(RELATIVE_PATH libJSBSim_PATH ${CMAKE_SOURCE_DIR} ${libJSBSim_DIRECTORY})
 

src/CMakeLists.txt

@@ -71,7 +71,11 @@ add_subdirectory(simgear)
 
 if(EXPAT_FOUND)
   include_directories(${EXPAT_INCLUDE_DIRS})
-  set(JSBSIM_LINK_LIBRARIES ${EXPAT_LIBRARIES} ${JSBSIM_LINK_LIBRARIES})
+  if (PKG_CONFIG_FOUND)
+    set(JSBSIM_LINK_LIBRARIES ${PC_EXPAT_LIBRARIES} ${JSBSIM_LINK_LIBRARIES})
+  else()
+    set(JSBSIM_LINK_LIBRARIES ${EXPAT_LIBRARIES} ${JSBSIM_LINK_LIBRARIES})
+  endif()
 endif()
 
 set(HEADERS FGFDMExec.h