Add version constraints for signal handler primitives in interpreter

src/crystal/interpreter.cr

@@ -25,12 +25,14 @@ module Crystal
     def self.fiber_resumable(context) : LibC::Long
     end
 
-    @[Primitive(:interpreter_signal_descriptor)]
-    def self.signal_descriptor(fd : Int32) : Nil
-    end
+    {% if compare_versions(Crystal::VERSION, "1.15.0-dev") >= 0 %}
+      @[Primitive(:interpreter_signal_descriptor)]
+      def self.signal_descriptor(fd : Int32) : Nil
+      end
 
-    @[Primitive(:interpreter_signal)]
-    def self.signal(signum : Int32, handler : Int32) : Nil
-    end
+      @[Primitive(:interpreter_signal)]
+      def self.signal(signum : Int32, handler : Int32) : Nil
+      end
+    {% end %}
   end
 end

src/crystal/system/unix/signal.cr

@@ -22,7 +22,7 @@ module Crystal::System::Signal
     @@mutex.synchronize do
       unless @@handlers[signal]?
         @@sigset << signal
-        {% if flag?(:interpreted) %}
+        {% if flag?(:interpreted) && Crystal::Interpreter.has_method?(:signal) %}
           Crystal::Interpreter.signal(signal.value, 2)
         {% else %}
           action = LibC::Sigaction.new
@@ -66,7 +66,7 @@ module Crystal::System::Signal
     else
       @@mutex.synchronize do
         @@handlers.delete(signal)
-        {% if flag?(:interpreted) %}
+        {% if flag?(:interpreted) && Crystal::Interpreter.has_method?(:signal) %}
           h = case handler
               when LibC::SIG_DFL then 0
               when LibC::SIG_IGN then 1
@@ -131,7 +131,7 @@ module Crystal::System::Signal
     ::Signal.each do |signal|
       next unless @@sigset.includes?(signal)
 
-      {% if flag?(:interpreted) %}
+      {% if flag?(:interpreted) && Crystal::Interpreter.has_method?(:signal) %}
         Crystal::Interpreter.signal(signal.value, 0)
       {% else %}
         LibC.signal(signal, LibC::SIG_DFL)
@@ -203,7 +203,7 @@ module Crystal::System::Signal
     @@sigset.clear
     start_loop
 
-    {% if flag?(:interpreted) %}
+    {% if flag?(:interpreted) && Interpreter.has_method?(:signal_descriptor) %}
       # replace the interpreter's writer pipe with the interpreted, so signals
       # will be received by the interpreter, but handled by the interpreted
       # signal loop

src/kernel.cr

@@ -630,6 +630,6 @@ end
   end
 {% end %}
 
-{% if flag?(:interpreted) && flag?(:unix) %}
+{% if flag?(:interpreted) && flag?(:unix) && Crystal::Interpreter.has_method?(:signal_descriptor) %}
   Crystal::System::Signal.setup_default_handlers
 {% end %}