Fix cmake crosscompiling (#60)

Allow the nodesize_dbg tool to be built when crosscompiling.  Link it statically to avoid anoying library search paths then use the crosscompiling emulator to run it to generate container_node_sizes_impl during the build.

Fixes #61.

src/CMakeLists.txt

@@ -77,9 +77,9 @@ set(src
 configure_file("config.hpp.in" "${CMAKE_CURRENT_BINARY_DIR}/config_impl.hpp")
 
 # generate container_node_sizes.hpp
-if(FOONATHAN_MEMORY_BUILD_TOOLS AND (NOT CMAKE_CROSSCOMPILING))
+if(FOONATHAN_MEMORY_BUILD_TOOLS)
     add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/container_node_sizes_impl.hpp
-            COMMAND foonathan_memory_node_size_debugger --code --alignof "FOONATHAN_ALIGNOF(T)" ${CMAKE_CURRENT_BINARY_DIR}/container_node_sizes_impl.hpp
+            COMMAND ${CMAKE_CROSSCOMPILING_EMULATOR} $<TARGET_FILE:foonathan_memory_node_size_debugger> --code --alignof "FOONATHAN_ALIGNOF(T)" ${CMAKE_CURRENT_BINARY_DIR}/container_node_sizes_impl.hpp
             DEPENDS foonathan_memory_node_size_debugger
             VERBATIM)
 else()

tool/CMakeLists.txt

@@ -5,6 +5,10 @@
 # builds tools
 
 add_executable(foonathan_memory_node_size_debugger test_types.hpp node_size_debugger.hpp node_size_debugger.cpp)
+if (CMAKE_CROSSCOMPILING)
+    # statically link when cross compiling so emulator doesn't need library paths
+    set_target_properties(foonathan_memory_node_size_debugger PROPERTIES LINK_FLAGS "-static")
+endif()
 _foonathan_use_comp(foonathan_memory_node_size_debugger)
 comp_target_features(foonathan_memory_node_size_debugger PUBLIC CPP11)
 if (MSVC)