Drop GccLtXX flags, require GCC > 4.7 and up

cfg/system.config.in

@@ -33,9 +33,6 @@ ar-supports-at-file = @ArSupportsAtFile@
 cc-clang-backend    = @CC_CLANG_BACKEND@
 cc-llvm-backend     = @CC_LLVM_BACKEND@
 gcc-is-clang        = @GccIsClang@
-gcc-lt-34           = @GccLT34@
-gcc-lt-44           = @GccLT44@
-gcc-lt-46           = @GccLT46@
 hs-cpp-args         = @HaskellCPPArgs@
 
 # Build options:

src/Oracles/Flag.hs

@@ -11,9 +11,6 @@ import Oracles.Setting
 data Flag = ArSupportsAtFile
           | CrossCompiling
           | GccIsClang
-          | GccLt34
-          | GccLt44
-          | GccLt46
           | GhcUnregisterised
           | LeadingUnderscore
           | SolarisBrokenShld
@@ -30,9 +27,6 @@ flag f = do
             ArSupportsAtFile   -> "ar-supports-at-file"
             CrossCompiling     -> "cross-compiling"
             GccIsClang         -> "gcc-is-clang"
-            GccLt34            -> "gcc-lt-34"
-            GccLt44            -> "gcc-lt-44"
-            GccLt46            -> "gcc-lt-46"
             GhcUnregisterised  -> "ghc-unregisterised"
             LeadingUnderscore  -> "leading-underscore"
             SolarisBrokenShld  -> "solaris-broken-shld"

src/Settings/Builders/Common.hs

@@ -40,12 +40,11 @@ cArgs = mempty
 
 -- TODO: should be in a different file
 cWarnings :: Args
-cWarnings = do
-    let gccGe46 = notM (flag GccIsClang ||^ flag GccLt46)
+cWarnings =
     mconcat [ arg "-Wall"
             , flag GccIsClang ? arg "-Wno-unknown-pragmas"
-            , gccGe46 ? notM windowsHost ? arg "-Werror=unused-but-set-variable"
-            , gccGe46 ? arg "-Wno-error=inline" ]
+            , notM (flag GccIsClang) ? notM windowsHost ? arg "-Werror=unused-but-set-variable"
+            , notM (flag GccIsClang) ? arg "-Wno-error=inline" ]
 
 bootPackageDatabaseArgs :: Args
 bootPackageDatabaseArgs = do

src/Settings/Packages/GhcPrim.hs

@@ -8,6 +8,5 @@ ghcPrimPackageArgs = package ghcPrim ? mconcat
     [ builder GhcCabal ? arg "--flag=include-ghc-prim"
 
     , builder (Cc CompileC)     ?
-      (not <$> flag GccLt44)    ?
       (not <$> flag GccIsClang) ?
       input "//cbits/atomic.c"  ? arg "-Wno-sync-nand" ]

src/Settings/Packages/Rts.hs

@@ -204,7 +204,7 @@ rtsPackageArgs = package rts ? do
 rtsWarnings :: Args
 rtsWarnings = mconcat
     [ pure ["-Wall", "-Werror"]
-    , flag GccLt34 ? arg "-W", not <$> flag GccLt34 ? arg "-Wextra"
+    , arg "-Wextra"
     , arg "-Wstrict-prototypes"
     , arg "-Wmissing-prototypes"
     , arg "-Wmissing-declarations"
@@ -214,5 +214,5 @@ rtsWarnings = mconcat
     , arg "-Wmissing-noreturn"
     , arg "-Wnested-externs"
     , arg "-Wredundant-decls"
-    , not <$> flag GccLt46 ? arg "-Wundef"
+    , arg "-Wundef"
     , arg "-fno-strict-aliasing" ]

src/Settings/Warnings.hs

@@ -12,9 +12,8 @@ defaultGhcWarningsArgs :: Args
 defaultGhcWarningsArgs = mconcat
     [ notStage0 ? pure [ "-Werror", "-Wnoncanonical-monad-instances" ]
     , (not <$> flag GccIsClang) ? mconcat
-      [ (not <$> flag GccLt46) ?
-        (not <$> windowsHost ) ? arg "-optc-Werror=unused-but-set-variable"
-      , (not <$> flag GccLt44) ? arg "-optc-Wno-error=inline" ]
+      [ (not <$> windowsHost ) ? arg "-optc-Werror=unused-but-set-variable"
+      , arg "-optc-Wno-error=inline" ]
     , flag GccIsClang ? arg "-optc-Wno-unknown-pragmas" ]
 
 -- | Package-specific warnings-related arguments, mostly suppressing various warnings.