ObjImporter: compile with exceptions enabled on Emscripten.

Actually looking forward to when I rewrite this whole thing.

doc/changelog.dox

@@ -196,6 +196,9 @@ See also:
 -   Suppressed a warning specific to MinGW GCC 8+ (see
     [mosra/magnum#474](https://github.com/mosra/magnum/issues/474))
 -   Linux and Emscripten builds were migrated from Travis to Circle CI
+-   @ref Trade::ObjImporter "ObjImporter" uses exceptions internally and needs
+    an explicit exception-enabling flag when built with Emscripten 1.39.0 and
+    newer
 
 @subsection changelog-latest-bugfixes Bug fixes
 

src/MagnumPlugins/ObjImporter/CMakeLists.txt

@@ -50,6 +50,13 @@ if(CMAKE_RUNTIME_OUTPUT_DIRECTORY AND CMAKE_LIBRARY_OUTPUT_DIRECTORY AND CMAKE_A
         LIBRARY_OUTPUT_DIRECTORY ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/magnum$<$<CONFIG:Debug>:-d>/importers
         ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_ARCHIVE_OUTPUT_DIRECTORY}/magnum$<$<CONFIG:Debug>:-d>/importers)
 endif()
+if(CORRADE_TARGET_EMSCRIPTEN)
+    # Since 1.39.0, this needs to be enabled on the plugin. Before (on 1.38.44
+    # at least) this wasn't needed, at least for the test -- having it enabled
+    # for the test binary and in the linker was enough. Most probably related
+    # to fastcomp->llvm backend switch.
+    set_property(TARGET ObjImporter APPEND_STRING PROPERTY COMPILE_FLAGS " -s DISABLE_EXCEPTION_CATCHING=0")
+endif()
 
 install(FILES ObjImporter.h ${CMAKE_CURRENT_BINARY_DIR}/configure.h
     DESTINATION ${MAGNUM_PLUGINS_INCLUDE_INSTALL_DIR}/ObjImporter)