diff --git a/pkgs/build-support/clang-wrapper/clang-wrapper.sh b/pkgs/build-support/clang-wrapper/clang-wrapper.sh
index 57715274f1e..3c6a9c8e452 100644
--- a/pkgs/build-support/clang-wrapper/clang-wrapper.sh
+++ b/pkgs/build-support/clang-wrapper/clang-wrapper.sh
@@ -138,13 +138,4 @@ if test -n "$NIX_CLANG_WRAPPER_EXEC_HOOK"; then
     source "$NIX_CLANG_WRAPPER_EXEC_HOOK"
 fi
 
-# Call the real `clang'.  Filter out warnings from stderr about unused
-# `-B' flags, since they confuse some programs.  Deep bash magic to
-# apply grep to stderr (by swapping stdin/stderr twice).
-if test -z "$NIX_CLANG_NEEDS_GREP"; then
-    @clangProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]}
-else
-    (@clangProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]} 3>&2 2>&1 1>&3- \
-        | (grep -v 'file path prefix' || true); exit ${PIPESTATUS[0]}) 3>&2 2>&1 1>&3-
-    exit $?
-fi    
+exec @clangProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]}
diff --git a/pkgs/build-support/gcc-cross-wrapper/gcc-wrapper.sh b/pkgs/build-support/gcc-cross-wrapper/gcc-wrapper.sh
index f954cae05d8..ec1f6004edd 100644
--- a/pkgs/build-support/gcc-cross-wrapper/gcc-wrapper.sh
+++ b/pkgs/build-support/gcc-cross-wrapper/gcc-wrapper.sh
@@ -114,13 +114,4 @@ fi
 # We want gcc to call the wrapper linker, not that of binutils.
 export PATH="@ldPath@:$PATH"
 
-# Call the real `gcc'.  Filter out warnings from stderr about unused
-# `-B' flags, since they confuse some programs.  Deep bash magic to
-# apply grep to stderr (by swapping stdin/stderr twice).
-if test -z "$NIX_GCC_NEEDS_GREP"; then
-    @gccProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]}
-else
-    (@gccProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]} 3>&2 2>&1 1>&3- \
-        | (grep -v 'file path prefix' || true); exit ${PIPESTATUS[0]}) 3>&2 2>&1 1>&3-
-    exit $?
-fi    
+exec @gccProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]}
diff --git a/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh b/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh
index 11ee8592932..d01ce54fd96 100644
--- a/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh
+++ b/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh
@@ -143,14 +143,4 @@ if test -n "$NIX_GCC_WRAPPER_EXEC_HOOK"; then
     source "$NIX_GCC_WRAPPER_EXEC_HOOK"
 fi
 
-
-# Call the real `gcc'.  Filter out warnings from stderr about unused
-# `-B' flags, since they confuse some programs.  Deep bash magic to
-# apply grep to stderr (by swapping stdin/stderr twice).
-if test -z "$NIX_GCC_NEEDS_GREP"; then
-    @gccProg@ ${extraBefore[@]} "${params[@]}" "${extraAfter[@]}"
-else
-    (@gccProg@ ${extraBefore[@]} "${params[@]}" "${extraAfter[@]}" 3>&2 2>&1 1>&3- \
-        | (grep -v 'file path prefix' || true); exit ${PIPESTATUS[0]}) 3>&2 2>&1 1>&3-
-    exit $?
-fi    
+exec @gccProg@ ${extraBefore[@]} "${params[@]}" "${extraAfter[@]}"
diff --git a/pkgs/build-support/gcc-wrapper/gnat-wrapper.sh b/pkgs/build-support/gcc-wrapper/gnat-wrapper.sh
index f6fa4b18400..4404194ff1b 100644
--- a/pkgs/build-support/gcc-wrapper/gnat-wrapper.sh
+++ b/pkgs/build-support/gcc-wrapper/gnat-wrapper.sh
@@ -100,14 +100,4 @@ if test -n "$NIX_GNAT_WRAPPER_EXEC_HOOK"; then
     source "$NIX_GNAT_WRAPPER_EXEC_HOOK"
 fi
 
-
-# Call the real `gcc'.  Filter out warnings from stderr about unused
-# `-B' flags, since they confuse some programs.  Deep bash magic to
-# apply grep to stderr (by swapping stdin/stderr twice).
-if test -z "$NIX_GNAT_NEEDS_GREP"; then
-    @gnatProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]}
-else
-    (@gnatProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]} 3>&2 2>&1 1>&3- \
-        | (grep -v 'file path prefix' || true); exit ${PIPESTATUS[0]}) 3>&2 2>&1 1>&3-
-    exit $?
-fi
+exec @gnatProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]}
diff --git a/pkgs/build-support/gcc-wrapper/gnatlink-wrapper.sh b/pkgs/build-support/gcc-wrapper/gnatlink-wrapper.sh
index 25907108b4d..d8e4b5254bf 100644
--- a/pkgs/build-support/gcc-wrapper/gnatlink-wrapper.sh
+++ b/pkgs/build-support/gcc-wrapper/gnatlink-wrapper.sh
@@ -30,14 +30,4 @@ if test -n "$NIX_GNAT_WRAPPER_EXEC_HOOK"; then
     source "$NIX_GNAT_WRAPPER_EXEC_HOOK"
 fi
 
-
-# Call the real `gcc'.  Filter out warnings from stderr about unused
-# `-B' flags, since they confuse some programs.  Deep bash magic to
-# apply grep to stderr (by swapping stdin/stderr twice).
-if test -z "$NIX_GNAT_NEEDS_GREP"; then
-    @gnatlinkProg@ ${extraBefore[@]} "$@" ${extraAfter[@]}
-else
-    (@gnatlinkProg@ ${extraBefore[@]} "$@" ${extraAfter[@]} 3>&2 2>&1 1>&3- \
-        | (grep -v 'file path prefix' || true); exit ${PIPESTATUS[0]}) 3>&2 2>&1 1>&3-
-    exit $?
-fi
+exec @gnatlinkProg@ ${extraBefore[@]} "$@" ${extraAfter[@]}
diff --git a/pkgs/stdenv/native/default.nix b/pkgs/stdenv/native/default.nix
index 715bc02758b..b0ed7c93f78 100644
--- a/pkgs/stdenv/native/default.nix
+++ b/pkgs/stdenv/native/default.nix
@@ -35,9 +35,6 @@ rec {
     alias sed=gsed
     export MAKE=gmake
     shopt -s expand_aliases
-
-    # Filter out stupid GCC warnings (in gcc-wrapper).
-    export NIX_GCC_NEEDS_GREP=1
   '';
 
   prehookOpenBSD = ''
@@ -52,9 +49,6 @@ rec {
 
     export MAKE=gmake
     shopt -s expand_aliases
-
-    # Filter out stupid GCC warnings (in gcc-wrapper).
-    export NIX_GCC_NEEDS_GREP=1
   '';
 
   prehookNetBSD = ''
@@ -65,9 +59,6 @@ rec {
     alias tar=gtar
     export MAKE=gmake
     shopt -s expand_aliases
-
-    # Filter out stupid GCC warnings (in gcc-wrapper).
-    export NIX_GCC_NEEDS_GREP=1
   '';
 
   prehookCygwin = ''