Merge pull request #17010 from compnerd/fcntl

Author: swift-ci

stdlib/public/Platform/ucrt.modulemap

@@ -78,6 +78,11 @@ module ucrt [system] {
     }
 
     module POSIX {
+      module fcntl {
+        header "fcntl.h"
+        export *
+      }
+
       module sys {
         export *