fix segfault on exit if no http section is defined in confguraiton,
the bug has been introduced in r1947

src/http/modules/perl/ngx_http_perl_module.c

diff --git a/src/http/modules/perl/ngx_http_perl_module.c b/src/http/modules/perl/ngx_http_perl_module.c
index 833e90f..a546212 100644
--- a/src/http/modules/perl/ngx_http_perl_module.c
+++ b/src/http/modules/perl/ngx_http_perl_module.c
@@ -1061,12 +1061,10 @@
 
     pmcf = ngx_http_cycle_get_module_main_conf(cycle, ngx_http_perl_module);
 
-    {
+    if (pmcf) {
+        dTHXa(pmcf->perl);
+        PERL_SET_CONTEXT(pmcf->perl);
 
-    dTHXa(pmcf->perl);
-    PERL_SET_CONTEXT(pmcf->perl);
-
-    PERL_SYS_TERM();
-
+        PERL_SYS_TERM();
     }
 }