SSL: avoid calling SSL_write() with zero data size. According to documentation, calling SSL_write() with num=0 bytes to be sent results in undefined behavior. We don't currently call ngx_ssl_send_chain() with empty chain and buffer. This check handles the case of a chain with total data size that is a multiple of NGX_SSL_BUFSIZE, and with the special buffer at the end. In practice such cases resulted in premature connection close and critical error "SSL_write() failed (SSL:)" in the error log.

ngx_addon_name=ngx_mysql

HTTP_MODULES="$HTTP_MODULES ngx_http_mysql_test_module"

HTTP_INCS="$HTTP_INCS $ngx_addon_dir"
HTTP_DEPS="$HTTP_DEPS $ngx_addon_dir/ngx_mysql.h"
#CORE_LIBS="$CORE_LIBS -lmd"

USE_SHA1=YES

NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_mysql.c"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_mysql_test.c"