diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 2afe15f..1f39903 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -973,7 +973,8 @@ data RtsOptsEnabled = RtsOptsNone | RtsOptsSafeOnly | RtsOptsAll
 -- this compilation.
 
 data Way
-  = WayThreaded
+  = WayCustom String
+  | WayThreaded
   | WayDebug
   | WayProf
   | WayEventLog
@@ -999,6 +1000,7 @@ allowed_combination way = and [ x `allowedWith` y
         _ `allowedWith` WayDebug                = True
         WayDebug `allowedWith` _                = True
 
+        (WayCustom {}) `allowedWith` _          = True
         WayProf `allowedWith` WayNDP            = True
         WayThreaded `allowedWith` WayProf       = True
         WayThreaded `allowedWith` WayEventLog   = True
@@ -1008,6 +1010,7 @@ mkBuildTag :: [Way] -> String
 mkBuildTag ways = concat (intersperse "_" (map wayTag ways))
 
 wayTag :: Way -> String
+wayTag (WayCustom xs) = xs
 wayTag WayThreaded = "thr"
 wayTag WayDebug    = "debug"
 wayTag WayDyn      = "dyn"
@@ -1018,6 +1021,7 @@ wayTag WayGran     = "mg"
 wayTag WayNDP      = "ndp"
 
 wayRTSOnly :: Way -> Bool
+wayRTSOnly (WayCustom {}) = False
 wayRTSOnly WayThreaded = True
 wayRTSOnly WayDebug    = True
 wayRTSOnly WayDyn      = False
@@ -1028,6 +1032,7 @@ wayRTSOnly WayGran     = False
 wayRTSOnly WayNDP      = False
 
 wayDesc :: Way -> String
+wayDesc (WayCustom xs) = xs
 wayDesc WayThreaded = "Threaded"
 wayDesc WayDebug    = "Debug"
 wayDesc WayDyn      = "Dynamic"
@@ -1038,6 +1043,7 @@ wayDesc WayGran     = "GranSim"
 wayDesc WayNDP      = "Nested data parallelism"
 
 wayGeneralFlags :: Platform -> Way -> [GeneralFlag]
+wayGeneralFlags _ (WayCustom {}) = []
 wayGeneralFlags _ WayThreaded = []
 wayGeneralFlags _ WayDebug = []
 wayGeneralFlags platform WayDyn =
@@ -1060,6 +1066,7 @@ wayGeneralFlags _ WayGran     = [Opt_GranMacros]
 wayGeneralFlags _ WayNDP      = []
 
 wayExtras :: Platform -> Way -> DynFlags -> DynFlags
+wayExtras _ (WayCustom {}) dflags = dflags
 wayExtras _ WayThreaded dflags = dflags
 wayExtras _ WayDebug    dflags = dflags
 wayExtras _ WayDyn      dflags = dflags
@@ -1071,6 +1078,7 @@ wayExtras _ WayNDP      dflags = setExtensionFlag' Opt_ParallelArrays
                                $ setGeneralFlag' Opt_Vectorise dflags
 
 wayOptc :: Platform -> Way -> [String]
+wayOptc _ (WayCustom {}) = []
 wayOptc platform WayThreaded = case platformOS platform of
                                OSOpenBSD -> ["-pthread"]
                                OSNetBSD  -> ["-pthread"]
@@ -1084,6 +1092,7 @@ wayOptc _ WayGran       = ["-DGRAN"]
 wayOptc _ WayNDP        = []
 
 wayOptl :: Platform -> Way -> [String]
+wayOptl _ (WayCustom {}) = []
 wayOptl platform WayThreaded =
         case platformOS platform of
         -- FreeBSD's default threading library is the KSE-based M:N libpthread,
@@ -1114,6 +1123,7 @@ wayOptl _ WayGran       = []
 wayOptl _ WayNDP        = []
 
 wayOptP :: Platform -> Way -> [String]
+wayOptP _ (WayCustom {}) = []
 wayOptP _ WayThreaded = []
 wayOptP _ WayDebug    = []
 wayOptP _ WayDyn      = []