Alex Fishman reported a curl_easy_escape() problem that was made the

function do wrong on all input bytes that are >= 0x80 (decimal 128) due to a
signed / unsigned mistake in the code. I fixed it and added test case 543 to
verify.

tests/data/Makefile.am

@@ -44,4 +44,4 @@ EXTRA_DIST = test1 test108 test117 test127 test20 test27 test34 test46	   \
  test409 test613 test614 test700 test701 test702 test704 test705 test703   \
  test706 test707 test350 test351 test352 test353 test289 test540 test354   \
  test231 test1000 test1001 test1002 test1003 test1004 test1005 test1006    \
- test615 test1007 test541 test1010 test1011 test1012
+ test615 test1007 test541 test1010 test1011 test1012 test542 test543

tests/data/test543

@@ -0,0 +1,35 @@
+<testcase>
+<info>
+<keywords>
+curl_easy_escape
+</keywords>
+</info>
+# Server-side
+
+# Client-side
+<client>
+<server>
+none
+</server>
+<tool>
+lib543
+</tool>
+ <name>
+curl_easy_escape
+ </name>
+ <command>
+-
+</command>
+
+</client>
+
+# Verify data after the test has been "shot"
+#
+# There's no MTDM in the protocol here since this code doesn't ask for the
+# time/date of the file
+<verify>
+<stdout>
+%9C%26K%3DI%04%A1%01%E0%D8%7C%20%B7%EFS%29%FA%1DW%E1
+</stdout>
+</verify>
+</testcase>