fix: apply -rdynamic unconditionally for GHC API programs

The previous fix checked `ways_ `hasWay` WayDyn` but this condition fails
when the test isn't compiled with -dynamic flag, even when linking against
dynamic libraries. In a dynamic-only GHC build, tests compiled without
-dynamic would not get -rdynamic added.

Changed condition from:
  ways_ `hasWay` WayDyn && any ((== "ghc") . unitPackageNameString) pkgs
to:
  blm /= FullyStatic && any ((== "ghc") . unitPackageNameString) pkgs

This ensures -rdynamic is added for any non-static executable linking
against the ghc package, regardless of -dynamic flag. This matches the
approach in ghc-iserv.cabal.in which applies these flags unconditionally.

The GHC API may load shared libraries at runtime via dlopen() (for GHCi,
Template Haskell, etc.) even when the executable wasn't compiled with
-dynamic. Only FullyStatic executables can skip this since they won't
load dynamic libraries.

Author: angerman

compiler/GHC/Linker/Static.hs

@@ -82,6 +82,12 @@ Platform-specific solutions:
   macOS: -flat_namespace (makes all symbols visible across namespaces)
   Windows: not needed (--enable-auto-import handles this)
 
+We apply this unconditionally for non-static executables linking against the
+ghc package, regardless of whether -dynamic is passed. This is because the
+GHC API may load shared libraries at runtime (via dlopen) even when the
+executable itself wasn't compiled with -dynamic. We only skip this for
+FullyStatic executables since they won't be loading dynamic libraries.
+
 This is the same issue that ghc-iserv faces, and is documented in
 utils/ghc-iserv/ghc-iserv.cabal.in as Note [ghc-iserv and dynamic symbol export].
 -}
@@ -271,7 +277,7 @@ linkBinary' staticLink logger tmpfs dflags blm unit_env o_files dep_units = do
                           else [])
 
                       -- See Note [Export dynamic symbols for GHC API programs]
-                      ++ (if ways_ `hasWay` WayDyn &&
+                      ++ (if blm /= FullyStatic &&
                              any ((== "ghc") . unitPackageNameString) pkgs
                           then case platformOS platform of
                                  os | osElfTarget os -> ["-rdynamic"]