check-exports: Use the return code of diff rather than the output

diff on Solaris prints 'No differences found' for matching files, which
makes the check-exports call fail regardless of whether the exports match
or not. Instead, use the return code of diff, which is 0 when the files match.

diff --git a/check-exports b/check-exports
index cd829b0..c6d3eca 100755 (executable)
--- a/check-exports
+++ b/check-exports
@@ -58,10 +58,11 @@ nm $NMARGS $lib_path | awk \
        > $lib_result
 
 diffoutput=`diff -u $def_path $lib_result`
+diffresult=$?
 
 rm $lib_result
 
-if test "x$diffoutput" = "x"; then
+if test "$diffresult" -eq 0; then
   exit 0;
 else
   echo -n "$diffoutput" >&2