diff --git a/Setup.hs b/Setup.hs
--- a/Setup.hs
+++ b/Setup.hs
@@ -1,40 +1,2 @@
 import Distribution.Simple
-import Distribution.Simple.Setup
-import Distribution.Simple.LocalBuildInfo
-import Distribution.PackageDescription
-import Distribution.Version
-
--- This checks the direct dependency of the bytestring package being
--- compiled against to set the bytestring_has_itoa_c and
--- bytestring_has_builder flags accordingly.
-
-main = defaultMainWithHooks simpleUserHooks {
-    confHook = \pkg flags ->
-      if null (configConstraints flags)
-      then do
-        confHook simpleUserHooks pkg flags
-      else do
-        let bytestring_version =
-                case [ versionBranch v
-                     | (Dependency pkg ver)  <- configConstraints flags
-                     , pkg == PackageName "bytestring"
-                     , (Just v) <- [isSpecificVersion ver] ]
-                  of
-                     [v] -> v
-                     vs   -> error ("error detecting bytestring version  "  ++ show vs)
-
-        let has_itoa_c  = ( FlagName "bytestring_has_itoa_c"
-                          , bytestring_version >= [0,10]      )
-
-        let has_builder = ( FlagName "bytestring_has_builder"
-                          , bytestring_version >= [0,10,4]   )
-
-        let update fs gs =
-                 fs ++ [ g | g <- gs, not $ any (\f -> fst f == fst g) fs]
-
-        let flags' = flags { configConfigurationsFlags =
-                                update [has_itoa_c, has_builder]
-                                       (configConfigurationsFlags flags) }
-            
-        confHook simpleUserHooks pkg flags'
-  }
+main = defaultMain
diff --git a/bytestring-builder.cabal b/bytestring-builder.cabal
--- a/bytestring-builder.cabal
+++ b/bytestring-builder.cabal
@@ -1,5 +1,5 @@
 name:                bytestring-builder
-version:             0.10.4.0.1
+version:             0.10.4.0.2
 synopsis:            The new bytestring builder, packaged outside of GHC
 description:
   This is the bytestring builder that is debuting in bytestring-0.10.4.0, which
@@ -32,7 +32,7 @@
 copyright:           (c) 2010 Jasper Van der Jeugt
                      (c) 2010-2013 Simon Meier
 category:            Data
-build-type:          Custom
+build-type:          Simple
 extra-source-files:
                      cbits/*.c
 
@@ -50,30 +50,23 @@
 source-repository this
   type:     git
   location: http://github.com/lpsmith/bytestring-builder
-  tag:      v0.10.4.0.1
-
--- Note that these flags are set by Setup.hs
-
-Flag bytestring_has_itoa_c
-  default: True
-  manual: True
+  tag:      v0.10.4.0.2
 
 Flag bytestring_has_builder
   default: True
-  manual: True
 
 library
   build-depends:     base >= 4.2 && < 5,
                      bytestring >= 0.9 && < 0.10.1 || == 0.10.4.*,
                      deepseq
 
-  if !flag(bytestring_has_itoa_c)
-      c-sources: cbits/itoa.c
-
-
-  if !flag(bytestring_has_builder)
+  if flag(bytestring_has_builder)
+      build-depends:     bytestring >= 0.10.4
+  else
+      build-depends:     bytestring < 0.10.4
       hs-source-dirs: src
-      c-sources: cbits/fpstring.c
+      c-sources: cbits/itoa.c
+                 cbits/fpstring.c
       exposed-modules:
                          Data.ByteString.Builder
                          Data.ByteString.Builder.Extra
diff --git a/cbits/fpstring.c b/cbits/fpstring.c
--- a/cbits/fpstring.c
+++ b/cbits/fpstring.c
@@ -3,7 +3,7 @@
 /* This wrapper is here so that we can copy a sub-range of a ByteArray#.
    We cannot construct a pointer to the interior of an unpinned ByteArray#,
    except by doing an unsafe ffi call, and adjusting the pointer C-side. */
-void * fps_memcpy_offsets(void       *dst, unsigned long dst_off,
+void * bytestring_builder_memcpy_offsets(void       *dst, unsigned long dst_off,
                           const void *src, unsigned long src_off, size_t n) {
     return memcpy(dst + dst_off, src + src_off, n);
 }
diff --git a/cbits/itoa.c b/cbits/itoa.c
--- a/cbits/itoa.c
+++ b/cbits/itoa.c
@@ -12,7 +12,7 @@
 static const char* digits = "0123456789abcdef";
 
 // signed integers
-char* _hs_bytestring_int_dec (int x, char* buf)
+char* bytestring_builder_int_dec (int x, char* buf)
 {
     char c, *ptr = buf, *next_free;
     int x_tmp;
@@ -48,7 +48,7 @@
 }
 
 // signed long long ints (64 bit integers)
-char* _hs_bytestring_long_long_int_dec (long long int x, char* buf)
+char* bytestring_builder_long_long_int_dec (long long int x, char* buf)
 {
     char c, *ptr = buf, *next_free;
     long long int x_tmp;
@@ -84,7 +84,7 @@
 }
 
 // unsigned integers
-char* _hs_bytestring_uint_dec (unsigned int x, char* buf)
+char* bytestring_builder_uint_dec (unsigned int x, char* buf)
 {
     char c, *ptr = buf, *next_free;
     unsigned int x_tmp;
@@ -107,7 +107,7 @@
 }
 
 // unsigned long ints
-char* _hs_bytestring_long_long_uint_dec (long long unsigned int x, char* buf)
+char* bytestring_builder_long_long_uint_dec (long long unsigned int x, char* buf)
 {
     char c, *ptr = buf, *next_free;
     long long unsigned int x_tmp;
@@ -136,7 +136,7 @@
 // Padded (9 digits), decimal, positive int:
 // We will use it with numbers that fit in 31 bits; i.e., numbers smaller than
 // 10^9, as "31 * log 2 / log 10 = 9.33"
-void _hs_bytestring_int_dec_padded9 (int x, char* buf)
+void bytestring_builder_int_dec_padded9 (int x, char* buf)
 {
     const int max_width_int32_dec = 9;
     char* ptr = buf + max_width_int32_dec;
@@ -156,7 +156,7 @@
 // Padded (19 digits), decimal, positive long long int:
 // We will use it with numbers that fit in 63 bits; i.e., numbers smaller than
 // 10^18, as "63 * log 2 / log 10 = 18.96"
-void _hs_bytestring_long_long_int_dec_padded18 (long long int x, char* buf)
+void bytestring_builder_long_long_int_dec_padded18 (long long int x, char* buf)
 {
     const int max_width_int64_dec = 18;
     char* ptr = buf + max_width_int64_dec;
@@ -179,7 +179,7 @@
 ///////////////////////
 
 // unsigned ints (32 bit words)
-char* _hs_bytestring_uint_hex (unsigned int x, char* buf) {
+char* bytestring_bytestring_uint_hex (unsigned int x, char* buf) {
     // write hex representation in reverse order
     char c, *ptr = buf, *next_free;
     do {
@@ -197,7 +197,7 @@
 };
 
 // unsigned long ints (64 bit words)
-char* _hs_bytestring_long_long_uint_hex (long long unsigned int x, char* buf) {
+char* bytestring_bytestring_long_long_uint_hex (long long unsigned int x, char* buf) {
     // write hex representation in reverse order
     char c, *ptr = buf, *next_free;
     do {
diff --git a/src/Data/ByteString/Builder/ASCII.hs b/src/Data/ByteString/Builder/ASCII.hs
--- a/src/Data/ByteString/Builder/ASCII.hs
+++ b/src/Data/ByteString/Builder/ASCII.hs
@@ -357,10 +357,10 @@
                     PAIR(q,r) -> fromInteger q : fromInteger r : putB ns
 
 
-foreign import ccall unsafe "static _hs_bytestring_int_dec_padded9"
+foreign import ccall unsafe "static bytestring_builder_int_dec_padded9"
     c_int_dec_padded9 :: CInt -> Ptr Word8 -> IO ()
 
-foreign import ccall unsafe "static _hs_bytestring_long_long_int_dec_padded18"
+foreign import ccall unsafe "static bytestring_builder_long_long_int_dec_padded18"
     c_long_long_int_dec_padded18 :: CLLong -> Ptr Word8 -> IO ()
 
 {-# INLINE intDecPadded #-}
diff --git a/src/Data/ByteString/Builder/Internal.hs b/src/Data/ByteString/Builder/Internal.hs
--- a/src/Data/ByteString/Builder/Internal.hs
+++ b/src/Data/ByteString/Builder/Internal.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE ScopedTypeVariables, CPP, BangPatterns, RankNTypes #-}
-#if __GLASGOW_HASKELL__ >= 703
+#if __GLASGOW_HASKELL__ >= 701
 {-# LANGUAGE Unsafe #-}
 #endif
 {-# OPTIONS_HADDOCK hide #-}
diff --git a/src/Data/ByteString/Builder/Prim/ASCII.hs b/src/Data/ByteString/Builder/Prim/ASCII.hs
--- a/src/Data/ByteString/Builder/Prim/ASCII.hs
+++ b/src/Data/ByteString/Builder/Prim/ASCII.hs
@@ -100,10 +100,10 @@
 -- Signed integers
 ------------------
 
-foreign import ccall unsafe "static _hs_bytestring_int_dec" c_int_dec
+foreign import ccall unsafe "static bytestring_builder_int_dec" c_int_dec
     :: CInt -> Ptr Word8 -> IO (Ptr Word8)
 
-foreign import ccall unsafe "static _hs_bytestring_long_long_int_dec" c_long_long_int_dec
+foreign import ccall unsafe "static bytestring_builder_long_long_int_dec" c_long_long_int_dec
     :: CLLong -> Ptr Word8 -> IO (Ptr Word8)
 
 {-# INLINE encodeIntDecimal #-}
@@ -142,10 +142,10 @@
 -- Unsigned integers
 --------------------
 
-foreign import ccall unsafe "static _hs_bytestring_uint_dec" c_uint_dec
+foreign import ccall unsafe "static bytestring_builder_uint_dec" c_uint_dec
     :: CUInt -> Ptr Word8 -> IO (Ptr Word8)
 
-foreign import ccall unsafe "static _hs_bytestring_long_long_uint_dec" c_long_long_uint_dec
+foreign import ccall unsafe "static bytestring_builder_long_long_uint_dec" c_long_long_uint_dec
     :: CULLong -> Ptr Word8 -> IO (Ptr Word8)
 
 {-# INLINE encodeWordDecimal #-}
@@ -186,10 +186,10 @@
 -- without lead
 ---------------
 
-foreign import ccall unsafe "static _hs_bytestring_uint_hex" c_uint_hex
+foreign import ccall unsafe "static bytestring_bytestring_uint_hex" c_uint_hex
     :: CUInt -> Ptr Word8 -> IO (Ptr Word8)
 
-foreign import ccall unsafe "static _hs_bytestring_long_long_uint_hex" c_long_long_uint_hex
+foreign import ccall unsafe "static bytestring_bytestring_long_long_uint_hex" c_long_long_uint_hex
     :: CULLong -> Ptr Word8 -> IO (Ptr Word8)
 
 {-# INLINE encodeWordHex #-}
diff --git a/src/Data/ByteString/Builder/Prim/Internal.hs b/src/Data/ByteString/Builder/Prim/Internal.hs
--- a/src/Data/ByteString/Builder/Prim/Internal.hs
+++ b/src/Data/ByteString/Builder/Prim/Internal.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE ScopedTypeVariables, CPP, BangPatterns #-}
-#if __GLASGOW_HASKELL__ >= 703
+#if __GLASGOW_HASKELL__ >= 701
 {-# LANGUAGE Unsafe #-}
 #endif
 {-# OPTIONS_HADDOCK hide #-}
diff --git a/src/Data/ByteString/Short/Internal.hs b/src/Data/ByteString/Short/Internal.hs
--- a/src/Data/ByteString/Short/Internal.hs
+++ b/src/Data/ByteString/Short/Internal.hs
@@ -2,7 +2,7 @@
              ForeignFunctionInterface, MagicHash, UnboxedTuples,
              UnliftedFFITypes #-}
 {-# OPTIONS_GHC -fno-warn-name-shadowing #-}
-#if __GLASGOW_HASKELL__ >= 703
+#if __GLASGOW_HASKELL__ >= 701
 {-# LANGUAGE Unsafe #-}
 #endif
 {-# OPTIONS_HADDOCK hide #-}
@@ -535,7 +535,7 @@
           copyAddrToByteArray# src dst 0# len s
         = copyAddrToByteArray0 src dst    len s  #-}
 
-foreign import ccall unsafe "fpstring.h fps_memcpy_offsets"
+foreign import ccall unsafe "fpstring.h bytestring_builder_memcpy_offsets"
   memcpy_AddrToByteArray :: MutableByteArray# s -> CLong -> Addr# -> CLong -> CSize -> IO ()
 
 foreign import ccall unsafe "string.h memcpy"
@@ -556,7 +556,7 @@
           copyByteArrayToAddr# src 0# dst len s
         = copyByteArrayToAddr0 src    dst len s  #-}
 
-foreign import ccall unsafe "fpstring.h fps_memcpy_offsets"
+foreign import ccall unsafe "fpstring.h bytestring_builder_memcpy_offsets"
   memcpy_ByteArrayToAddr :: Addr# -> CLong -> ByteArray# -> CLong -> CSize -> IO ()
 
 foreign import ccall unsafe "string.h memcpy"
@@ -583,7 +583,7 @@
     unST (ST st) = st
     unST_ st s = case unST st s of (# s, _ #) -> s
 
-foreign import ccall unsafe "fpstring.h fps_memcpy_offsets"
+foreign import ccall unsafe "fpstring.h bytestring_builder_memcpy_offsets"
   memcpy_ByteArray :: MutableByteArray# s -> CLong
                    -> ByteArray# -> CLong -> CSize -> IO ()
 #endif