t9902: mingw-specific fix for gitfile link files

The path in a .git platform independent link file needs to be absolute
and under mingw we need it to be a windows type path, not a unix style
path so it should start with a drive letter and not a /.

Signed-off-by: Pat Thoyts <[email protected]>

Author: patthoyts

t/t9902-completion.sh

@@ -213,8 +213,8 @@ test_expect_success '__gitdir - non-existing $GIT_DIR' '
 '
 
 test_expect_success '__gitdir - gitfile in cwd' '
-	echo "$(pwd -P)/otherrepo/.git" >expected &&
-	echo "gitdir: $TRASH_DIRECTORY/otherrepo/.git" >subdir/.git &&
+	echo "$(pwd -W)/otherrepo/.git" >expected &&
+	echo "gitdir: $(pwd -W)/otherrepo/.git" >subdir/.git &&
 	test_when_finished "rm -f subdir/.git" &&
 	(
 		cd subdir &&
@@ -224,8 +224,8 @@ test_expect_success '__gitdir - gitfile in cwd' '
 '
 
 test_expect_success '__gitdir - gitfile in parent' '
-	echo "$(pwd -P)/otherrepo/.git" >expected &&
-	echo "gitdir: $TRASH_DIRECTORY/otherrepo/.git" >subdir/.git &&
+	echo "$(pwd -W)/otherrepo/.git" >expected &&
+	echo "gitdir: $(pwd -W)/otherrepo/.git" >subdir/.git &&
 	test_when_finished "rm -f subdir/.git" &&
 	(
 		cd subdir/subsubdir &&