Wrap LibC.getaddrinfo in syscall(&) on UNIX and Windows 7

Author: ysbaddaden

src/crystal/system/unix/addrinfo.cr

@@ -49,7 +49,15 @@ module Crystal::System::Addrinfo
       end
     {% end %}
 
-    ret = LibC.getaddrinfo(domain, service.to_s, pointerof(hints), out ptr)
+    ptr = Pointer(LibC::Addrinfo).null
+    ret =
+      {% if flag?(:execution_context) %}
+        ::Fiber::ExecutionContext.syscall do
+          LibC.getaddrinfo(domain, service.to_s, pointerof(hints), pointerof(ptr))
+        end
+      {% else %}
+        LibC.getaddrinfo(domain, service.to_s, pointerof(hints), pointerof(ptr))
+      {% end %}
     unless ret.zero?
       if ret == LibC::EAI_SYSTEM
         raise ::Socket::Addrinfo::Error.from_os_error nil, Errno.value, domain: domain

src/crystal/system/win32/addrinfo_win7.cr

@@ -43,7 +43,15 @@ module Crystal::System::Addrinfo
       end
     end
 
-    ret = LibC.getaddrinfo(domain, service.to_s, pointerof(hints), out ptr)
+    ptr = Pointer(LibC::Addrinfo).null
+    ret =
+      {% if flag?(:execution_context) %}
+        ::Fiber::ExecutionContext.syscall do
+          LibC.getaddrinfo(domain, service.to_s, pointerof(hints), pointerof(ptr))
+        end
+      {% else %}
+        LibC.getaddrinfo(domain, service.to_s, pointerof(hints), pointerof(ptr))
+      {% end %}
     unless ret.zero?
       error = WinError.new(ret.to_u32!)
       raise ::Socket::Addrinfo::Error.from_os_error(nil, error, domain: domain, type: type, protocol: protocol, service: service)