[PATCH 4/4] mergetools/meld: Use '--output' when available

[David Aguilar <davvid@gmail.com>]

meld 1.5.0 and newer allow the output file to be specified
when merging multiple files.  Check the meld version and use
the '--output' option when available.

Signed-off-by: David Aguilar <davvid@gmail.com>
---
 mergetools/meld |   33 ++++++++++++++++++++++++++++++++-
 1 files changed, 32 insertions(+), 1 deletions(-)

diff --git a/mergetools/meld b/mergetools/meld
index 73d70ae..1923797 100644
--- a/mergetools/meld
+++ b/mergetools/meld
@@ -4,6 +4,37 @@ diff_cmd () {
 
 merge_cmd () {
 	touch "$BACKUP"
-	"$merge_tool_path" "$LOCAL" "$MERGED" "$REMOTE"
+	if test "$meld_has_output_option" = true
+	then
+		"$merge_tool_path" --output "$MERGED" \
+			"$BASE" "$LOCAL" "$REMOTE"
+	else
+		"$merge_tool_path" "$LOCAL" "$MERGED" "$REMOTE"
+	fi
 	check_unchanged
 }
+
+check_meld_version () {
+	if test -n "$meld_version_checked"
+	then
+		return
+	fi
+	# Whether 'meld --output <file>' is supported
+	meld_has_output_option=false
+
+	# Filter meld --version to contain numbers and dots only
+	meld="$(meld --version 2>/dev/null | sed -e 's/[^0-9.]\+//g')"
+	meld="${meld:-0.0.0}"
+
+	meld_major="$(expr "$meld" : '\([0-9]\{1,\}\)' || echo 0)"
+	meld_minor="$(expr "$meld" : '[0-9]\{1,\}\.\([0-9]\{1,\}\)' || echo 0)"
+
+	# 'meld --output <file>' was introduced in meld 1.5.0
+	if test "$meld_major" -gt 1 ||
+		(test "$meld_major" = 1 && test "$meld_minor" -ge 5)
+	then
+		meld_has_output_option=true
+	fi
+	meld_version_checked=true
+}
+check_meld_version
-- 
1.7.6.476.g57292