Allow gzflush() to write empty gzip members.

Before this, a gzflush() with Z_FINISH and no data to write would
do nothing. Now it will write an empty gzip member.

1 files changed, 3 insertions, 2 deletions

diff --git a/gzwrite.c b/gzwrite.c
index ef9ffee..1fd2046 100644
--- a/gzwrite.c
+++ b/gzwrite.c
@@ -88,8 +88,9 @@ local int gz_comp(gz_statep state, int flush) {
 
     /* check for a pending reset */
     if (state->reset) {
-        /* don't start a new gzip member unless there is data to write */
-        if (strm->avail_in == 0)
+        /* don't start a new gzip member unless there is data to write and
+           we're not flushing */
+        if (strm->avail_in == 0 && flush == Z_NO_FLUSH)
             return 0;
         deflateReset(strm);
         state->reset = 0;