add support for Conan managed dependencies

Signed-off-by: Jeroen Koekkoek <jeroen@koekkoek.nl>

conanfile.txt

@@ -0,0 +1,6 @@
+[requires]
+cunit/2.1-3@atolab/stable
+criterion/2.3.2@atolab/stable
+
+[generators]
+cmake

src/CMakeLists.txt

@@ -51,6 +51,32 @@ if(${CMAKE_C_COMPILER_ID} STREQUAL "SunPro")
   set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_LINKER_FLAGS} -m64")
 endif()
 
+# Conan
+if(EXISTS "${CMAKE_BINARY_DIR}/conanbuildinfo.cmake")
+  include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
+  if(APPLE)
+    # By default Conan strips all RPATHs (see conanbuildinfo.cmake), which
+    # causes tests to fail as the executables cannot find the library target.
+    # By setting KEEP_RPATHS, Conan does not set CMAKE_SKIP_RPATH and the
+    # resulting binaries still have the RPATH information. This is fine because
+    # CMake will strip the build RPATH information in the install step.
+    #
+    # NOTE:
+    # Conan's default approach is to use the "imports" feature, which copies
+    # all the dependencies into the bin directory. Of course, this doesn't work
+    # quite that well for libraries generated in this Project (see Conan
+    # documentation).
+    #
+    # See the links below for more information.
+    # https://github.com/conan-io/conan/issues/337
+    # https://docs.conan.io/en/latest/howtos/manage_shared_libraries/rpaths.html
+    # https://gitlab.kitware.com/cmake/community/wikis/doc/cmake/RPATH-handling
+    conan_basic_setup(KEEP_RPATHS)
+  else()
+    conan_basic_setup()
+  endif()
+endif()
+
 include(FileIDs)
 include(GNUInstallDirs)
 include(AnalyzeBuild)