[Qemu-devel] [PATCHv2] 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>
---

v2 addresses Peter Maydell review, and keeps the log before help in
case --help isn't given.

configure | 42 +++++++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 15 deletions(-)

diff --git a/configure b/configure
index f02510b..71dee54 100755
--- a/configure
+++ b/configure
@@ -29,14 +29,26 @@ TMPL="${TMPDIR1}/${TMPB}.lo"
 TMPA="${TMPDIR1}/lib${TMPB}.la"
 TMPE="${TMPDIR1}/${TMPB}.exe"
 
-rm -f config.log
+for i in "$@"; do
+case $i in
+    --help|-h) show_help=yes
+    ;;
+esac
+done
 
-# 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
+if test x"$show_help" = x"yes" ; then
+    CONFIG_LOG="/dev/null"
+else
+    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"
+fi
 
 error_exit() {
     echo
@@ -54,8 +66,8 @@ 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 +81,8 @@ 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 +129,8 @@ 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 +144,8 @@ 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." \
-- 
2.4.3