jack: do not try to use UMP when headers are from JACK1

Author: jcelerier

cmake/libremidi.jack.cmake

@@ -32,6 +32,15 @@ endif()
 if(LIBREMIDI_HAS_JACK)
   target_compile_definitions(libremidi ${_public} LIBREMIDI_JACK)
   if(LIBREMIDI_HAS_WEAKJACK)
-    target_compile_definitions(libremidi ${_public} LIBREMIDI_WEAKJACK)
+    target_compile_definitions(libremidi ${_public} LIBREMIDI_WEAKJACK LIBREMIDI_HAS_JACK_GET_VERSION)
+  else()
+    # JACK1 did not have LIBREMIDI_HAS_JACK_GET_VERSION. Just skip building the UMP binding in that case...
+    block()
+      set(CMAKE_REQUIRED_INCLUDES $<BUILD_INTERFACE:${JACK_PATH}>)
+      check_cxx_source_compiles("#include <jack/jack.h>\nint main() { return sizeof(jack_get_version); }" LIBREMIDI_HAS_JACK_GET_VERSION)
+      if(LIBREMIDI_HAS_JACK_GET_VERSION)
+        target_compile_definitions(libremidi ${_public} LIBREMIDI_HAS_JACK_GET_VERSION)
+      endif()
+    endblock()
   endif()
 endif()

include/libremidi/backends.hpp

@@ -29,7 +29,9 @@
 
 #if defined(LIBREMIDI_JACK)
   #include <libremidi/backends/jack.hpp>
-  #include <libremidi/backends/jack_ump.hpp>
+  #if defined(LIBREMIDI_HAS_JACK_GET_VERSION)
+    #include <libremidi/backends/jack_ump.hpp>
+  #endif
 #endif
 
 #if defined(LIBREMIDI_PIPEWIRE)
@@ -175,7 +177,7 @@ static constexpr auto available_backends = make_tl(
     ,
     net_ump::backend{}
 #endif
-#if defined(LIBREMIDI_JACK)
+#if defined(LIBREMIDI_JACK) && defined(LIBREMIDI_HAS_JACK_GET_VERSION)
     ,
     jack_ump::backend{}
 #endif