Disable Cabal RPath handling on untested Operating Systems

These operating systems do support RPath, but they are untested
with regards to Cabal's RPATH calculation, so we will leave
RPATH handling on those operating systems to GHC.

Cabal/Distribution/Simple/GHC.hs

@@ -1133,14 +1133,21 @@ getRPaths lbi clbi | supportRPaths hostOS = do
   where
     (Platform _ hostOS) = hostPlatform lbi
 
+    -- The list of RPath-supported operating systems below reflects the
+    -- platforms on which Cabal's RPATH handling is tested. It does _NOT_
+    -- reflect whether the OS supports RPATH.
+
+    -- E.g. when this comment was written, the *BSD operating systems were
+    -- untested with regards to Cabal RPATH handling, and were hence set to
+    -- 'False', while those operating systems themselves do support RPATH.
     supportRPaths Linux       = True
     supportRPaths Windows     = False
     supportRPaths OSX         = True
-    supportRPaths FreeBSD     = True
-    supportRPaths OpenBSD     = True
-    supportRPaths NetBSD      = True
-    supportRPaths DragonFly   = True
-    supportRPaths Solaris     = True
+    supportRPaths FreeBSD     = False
+    supportRPaths OpenBSD     = False
+    supportRPaths NetBSD      = False
+    supportRPaths DragonFly   = False
+    supportRPaths Solaris     = False
     supportRPaths AIX         = False
     supportRPaths HPUX        = False
     supportRPaths IRIX        = False