Add FindLTDL cmake module

As mentionned in FindLTDL.cmake, this is code that is hereby relicensed
under GPLv3.

closes #68

CMakeLists.txt

@@ -42,6 +42,7 @@ find_package(SDL 1.2.10 REQUIRED)
 find_package(SDL_image 1.2 REQUIRED)
 find_package(SDL_ttf 2.0 REQUIRED)
 find_package(PNG 1.2 REQUIRED)
+find_package(LTDL 2.4.2 REQUIRED)
 
 set(Boost_USE_STATIC_LIBS        ON)
 set(Boost_USE_MULTITHREADED      ON)

cmake/FindLTDL.cmake

@@ -0,0 +1,30 @@
+# Find the native LTDL includes and library
+# Copied verbatim from
+# http://code.metager.de/source/xref/hshannover/trust/tnc-fhh/shared/cmake_modules/FindLTDL.cmake
+# The above version was under GPL-2, this one is under GPL-3, for consistency
+# with the rest of the colobot project.
+#
+# This module defines
+#  LTDL_INCLUDE_DIR, where to find ltdl.h, etc.
+#  LTDL_LIBRARY, where to find the LTDL library.
+#  LTDL_FOUND, If false, do not try to use LTDL.
+
+FIND_PATH(LTDL_INCLUDE_DIR ltdl.h)
+
+FIND_LIBRARY(LTDL_LIBRARY ltdl)
+
+IF (LTDL_INCLUDE_DIR AND LTDL_LIBRARY)
+   SET(LTDL_FOUND TRUE)
+ELSE(LTDL_INCLUDE_DIR AND LTDL_LIBRARY)
+   SET(LTDL_FOUND FALSE)
+ENDIF (LTDL_INCLUDE_DIR AND LTDL_LIBRARY)
+
+IF (LTDL_FOUND)
+   IF (NOT LTDL_FIND_QUIETLY)
+      MESSAGE(STATUS "Found LTDL: ${LTDL_LIBRARY}")
+   ENDIF (NOT LTDL_FIND_QUIETLY)
+ELSE (LTDL_FOUND)
+   IF (LTDL_FIND_REQUIRED)
+      MESSAGE(FATAL_ERROR "Could not find LTDL")
+   ENDIF (LTDL_FIND_REQUIRED)
+ENDIF (LTDL_FOUND)

src/CMakeLists.txt

@@ -173,7 +173,7 @@ ${PNG_LIBRARIES}
 ${OPTIONAL_LIBS}
 ${PLATFORM_LIBS}
 ${Boost_LIBRARIES}
-ltdl
+${LTDL_LIBRARY}
 CBot
 )
 

src/plugins/test/CMakeLists.txt

@@ -9,4 +9,4 @@ include_directories(".")
 include_directories("../../")
 include_directories("../../../")
 
-target_link_libraries(manager_test ltdl)
+target_link_libraries(manager_test ${LTDL_LIBRARY})

src/sound/plugins/oalsound/test/CMakeLists.txt

@@ -8,4 +8,4 @@ add_executable(plugin_test plugin_test.cpp ../../../../common/iman.cpp ../../../
 include_directories(".")
 include_directories("../../../../")
 
-target_link_libraries(plugin_test ltdl)
+target_link_libraries(plugin_test ${LTDL_LIBRARY})