From a85877edaf9c9bc0b7721fd353d77629f9dc5867 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Wed, 13 Jul 2005 08:45:57 +0000
Subject: [PATCH] * r3317 was wrong: grep should be applied to gcc's stderr,
 not stdout.

svn path=/nixpkgs/trunk/; revision=3329
---
 pkgs/build-support/gcc-wrapper/gcc-wrapper.sh | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh b/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh
index 0e5b90bb877c..4db12afb5ce8 100644
--- a/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh
+++ b/pkgs/build-support/gcc-wrapper/gcc-wrapper.sh
@@ -113,8 +113,9 @@ if test -n "$NIX_GCC_WRAPPER_EXEC_HOOK"; then
 fi
 
 
-# Call the real `gcc'.  Filter out warnings about unused `-B' flags,
-# since they confuse some programs.
-@gccProg@ ${extraBefore[@]} "${params[@]}" ${extraAfter[@]} \
-    | (grep -v 'file path prefix' || true)
-exit ${PIPESTATUS[0]}
+# 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).
+(@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 $?