Dynamically link all loaded packages in new object

Summary:
As a result of fixing #8935 we needed to open shared libraries
with RTLD_LOCAL and so symbols from packages loaded earlier
cannot be found anymore. We need to include in the link all
packages loaded so far.

This fixes #10058

Test Plan: validate

Reviewers: hvr, simonmar, austin

Reviewed By: austin

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D676

GHC Trac Issues: #10058

(cherry picked from commit 0fcc4543)

compiler/ghci/Linker.hs

@@ -846,7 +846,10 @@ dynLoadObjs dflags pls objs = do
                       buildTag = mkBuildTag [WayDyn],
                       outputFile = Just soFile
                   }
-    linkDynLib dflags2 objs []
+    -- link all "loaded packages" so symbols in those can be resolved
+    -- Note: We are loading packages with local scope, so to see the
+    -- symbols in this link we must link all loaded packages again.
+    linkDynLib dflags2 objs (pkgs_loaded pls)
     consIORef (filesToNotIntermediateClean dflags) soFile
     m <- loadDLL soFile
     case m of