Remove FindSDL2 find-module, use sdl2-config.cmake instead
This requires SDL >= 2.0.4.
Since <https://bugzilla.libsdl.org/show_bug.cgi?id=2464> was fixed in
SDL 2.0.4, SDL behaves as a CMake "config-file package", even if it was
not itself built using CMake: it installs a sdl2-config.cmake file to
${libdir}/cmake/SDL2, which tells CMake where to find SDL's headers and
library, analogous to a pkg-config .pc file.
As a result, we no longer need to copy/paste a "find-module package"
to be able to find a system copy of SDL >= 2.0.4 with find_package(SDL2).
Find-module packages are now discouraged by the CMake developers, in
favour of having upstream projects behave as config-file packages.
This results in a small API change: FindSDL2 used to set SDL2_INCLUDE_DIR
and SDL2_LIBRARY, but the standard behaviour for config-file packages is
to set <name>_INCLUDE_DIRS and <name>_LIBRARIES. Use the CONFIG keyword
to make sure we search in config-file package mode, and will not find a
FindSDL2.cmake in some other directory that implements the old interface.
In addition to deleting redundant code, this avoids some assumptions in
FindSDL2 about the layout of a SDL installation. The current libsdl2-dev
package in Debian breaks those assumptions; this is considered a bug
and will hopefully be fixed soon, but it illustrates how fragile these
assumptions can be. We can be more robust against different installation
layouts by relying on SDL's own CMake integration.
When linking to a copy of CMake in a non-standard location, users can
now set the SDL2_DIR or CMAKE_PREFIX_PATH environment variable to point
to it; previously, these users would have used the SDL2DIR environment
variable. This continues to be unnecessary if using matching system-wide
installations of CMake and SDL2, for example both from Debian.
#where to build libs and bins
set(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)
set(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)
#these variables are for non-makefile generators
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${EXECUTABLE_OUTPUT_PATH})
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY_DEBUG ${EXECUTABLE_OUTPUT_PATH})
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY_RELEASE ${EXECUTABLE_OUTPUT_PATH})
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBRARY_OUTPUT_PATH})
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY_DEBUG ${LIBRARY_OUTPUT_PATH})
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY_RELEASE ${LIBRARY_OUTPUT_PATH})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBRARY_OUTPUT_PATH})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY_RELEASE ${LIBRARY_OUTPUT_PATH})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY_DEBUG ${LIBRARY_OUTPUT_PATH})
#resource paths
if(UNIX AND NOT APPLE)
set(target_binary_install_dir "bin" CACHE PATH "install dest for binaries")
set(target_library_install_dir "lib${LIB_SUFFIX}" CACHE PATH "install dest for libs")
string(SUBSTRING "${DATA_INSTALL_DIR}" 0 1 sharepath_start)
if(${sharepath_start} MATCHES "/")
set(HEDGEWARS_DATADIR "${DATA_INSTALL_DIR}/")
else()
set(HEDGEWARS_DATADIR "${CMAKE_INSTALL_PREFIX}/${DATA_INSTALL_DIR}/")
endif()
set(HEDGEWARS_FULL_DATADIR "${HEDGEWARS_DATADIR}")
else()
set(target_binary_install_dir "./")
if(APPLE)
set(target_library_install_dir "../Frameworks/")
set(CMAKE_INSTALL_PREFIX "Hedgewars.app/Contents/MacOS/")
set(HEDGEWARS_DATADIR "../Resources/")
set(HEDGEWARS_FULL_DATADIR "/Applications/${CMAKE_INSTALL_PREFIX}/${HEDGEWARS_DATADIR}")
elseif(WIN32)
set(target_library_install_dir "./")
set(HEDGEWARS_DATADIR "./")
set(HEDGEWARS_FULL_DATADIR "${CMAKE_INSTALL_PREFIX}/")
link_directories("${EXECUTABLE_OUTPUT_PATH}" "${CMAKE_SOURCE_DIR}/misc/winutils/bin")
endif()
endif()
#RPATH SETTINGS
#necessary for dynamic libraries on UNIX, ignored elsewhere
#use, i.e. don't skip the full RPATH for the build tree
set(CMAKE_SKIP_BUILD_RPATH FALSE)
set(CMAKE_SKIP_INSTALL_RPATH FALSE)
#it's safe to use our RPATH because it is relative
set(CMAKE_BUILD_WITH_INSTALL_RPATH TRUE)
#add the automatically determined parts of the RPATH
#which point to directories outside the build tree to the install RPATH
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH FALSE)
if(APPLE)
#@rpath mangling
set(CMAKE_INSTALL_RPATH "@executable_path/../Frameworks")
#install_name_tool for libraries
set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR TRUE)
set(CMAKE_INSTALL_NAME_DIR "@executable_path/../Frameworks")
else(APPLE AND NOT (${CMAKE_INSTALL_PREFIX} MATCHES "/usr"))
#paths where to find libraries (final slash not optional):
# - the first is relative to the executable
# - the second is the same directory of the executable (so it runs in bin/)
# - the third one is the full path of the system dir
#source http://www.cmake.org/pipermail/cmake/2008-January/019290.html
#skip this if the install prefix is the standard one
set(CMAKE_INSTALL_RPATH "$ORIGIN/../${target_library_install_dir}/:$ORIGIN/:${CMAKE_INSTALL_PREFIX}/${target_library_install_dir}/")
endif(APPLE)