Core: improved ngx_pstrdup() error handling.

src/core/ngx_conf_file.c

diff --git a/src/core/ngx_conf_file.c b/src/core/ngx_conf_file.c
index d6b5cdf..ec3c1fa 100644
--- a/src/core/ngx_conf_file.c
+++ b/src/core/ngx_conf_file.c
@@ -781,6 +781,9 @@
 
         file.len = name.len++;
         file.data = ngx_pstrdup(cf->pool, &name);
+        if (file.data == NULL) {
+            return NGX_CONF_ERROR;
+        }
 
         ngx_log_debug1(NGX_LOG_DEBUG_CORE, cf->log, 0, "include %s", file.data);