[Qemu-devel] [PATCH] build-sys: keep current config.log on --help

["Marc-André Lureau" <marcandre.lureau@gmail.com>]

It's nice to keep the config.log used to configure the build.

Signed-off-by: Marc-André Lureau <marcandre.lureau@gmail.com>
---
 configure | 35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/configure b/configure
index 1626c2e..dcd15a9 100755
--- a/configure
+++ b/configure
@@ -29,14 +29,7 @@ TMPL="${TMPDIR1}/${TMPB}.lo"
 TMPA="${TMPDIR1}/lib${TMPB}.la"
 TMPE="${TMPDIR1}/${TMPB}.exe"
 
-rm -f config.log
-
-# Print a helpful header at the top of config.log
-echo "# QEMU configure log $(date)" >> config.log
-printf "# Configured with:" >> config.log
-printf " '%s'" "$0" "$@" >> config.log
-echo >> config.log
-echo "#" >> config.log
+CONFIG_LOG="/dev/null"
 
 error_exit() {
     echo
@@ -54,8 +47,8 @@ do_compiler() {
     # is compiler binary to execute.
     local compiler="$1"
     shift
-    echo $compiler "$@" >> config.log
-    $compiler "$@" >> config.log 2>&1 || return $?
+    echo $compiler "$@" >> "$CONFIG_LOG"
+    $compiler "$@" >> "$CONFIG_LOG" 2>&1 || return $?
     # Test passed. If this is an --enable-werror build, rerun
     # the test with -Werror and bail out if it fails. This
     # makes warning-generating-errors in configure test code
@@ -69,8 +62,8 @@ do_compiler() {
            return 0
         ;;
     esac
-    echo $compiler -Werror "$@" >> config.log
-    $compiler -Werror "$@" >> config.log 2>&1 && return $?
+    echo $compiler -Werror "$@" >> "$CONFIG_LOG"
+    $compiler -Werror "$@" >> "$CONFIG_LOG" 2>&1 && return $?
     error_exit "configure test passed without -Werror but failed with -Werror." \
         "This is probably a bug in the configure script. The failing command" \
         "will be at the bottom of config.log." \
@@ -117,8 +110,8 @@ do_libtool() {
     local mode=$1
     shift
     # Run the compiler, capturing its output to the log.
-    echo $libtool $mode --tag=CC $cc "$@" >> config.log
-    $libtool $mode --tag=CC $cc "$@" >> config.log 2>&1 || return $?
+    echo $libtool $mode --tag=CC $cc "$@" >> "$CONFIG_LOG"
+    $libtool $mode --tag=CC $cc "$@" >> "$CONFIG_LOG" 2>&1 || return $?
     # Test passed. If this is an --enable-werror build, rerun
     # the test with -Werror and bail out if it fails. This
     # makes warning-generating-errors in configure test code
@@ -132,8 +125,8 @@ do_libtool() {
            return 0
         ;;
     esac
-    echo $libtool $mode --tag=CC $cc -Werror "$@" >> config.log
-    $libtool $mode --tag=CC $cc -Werror "$@" >> config.log 2>&1 && return $?
+    echo $libtool $mode --tag=CC $cc -Werror "$@" >> "$CONFIG_LOG"
+    $libtool $mode --tag=CC $cc -Werror "$@" >> "$CONFIG_LOG" 2>&1 && return $?
     error_exit "configure test passed without -Werror but failed with -Werror." \
         "This is probably a bug in the configure script. The failing command" \
         "will be at the bottom of config.log." \
@@ -1384,6 +1377,16 @@ EOF
 exit 0
 fi
 
+rm -f config.log
+
+# Print a helpful header at the top of config.log
+echo "# QEMU configure log $(date)" >> config.log
+printf "# Configured with:" >> config.log
+printf " '%s'" "$0" "$@" >> config.log
+echo >> config.log
+echo "#" >> config.log
+CONFIG_LOG="config.log"
+
 # Now we have handled --enable-tcg-interpreter and know we're not just
 # printing the help message, bail out if the host CPU isn't supported.
 if test "$ARCH" = "unknown"; then
-- 
2.4.3