Support for building with nginx configured with PCRE2

Related changes in upstream:
nginx/nginx@c6fec0b
nginx/nginx@931acbf

Author: defanator

src/ngx_http_modsecurity_common.h

@@ -140,8 +140,13 @@ extern ngx_module_t ngx_http_modsecurity_module;
 int ngx_http_modsecurity_process_intervention (Transaction *transaction, ngx_http_request_t *r, ngx_int_t early_log);
 ngx_http_modsecurity_ctx_t *ngx_http_modsecurity_create_ctx(ngx_http_request_t *r);
 char *ngx_str_to_char(ngx_str_t a, ngx_pool_t *p);
+#if (NGX_PCRE2)
+#define ngx_http_modsecurity_pcre_malloc_init(x) NULL
+#define ngx_http_modsecurity_pcre_malloc_done(x) (void)x
+#else
 ngx_pool_t *ngx_http_modsecurity_pcre_malloc_init(ngx_pool_t *pool);
 void ngx_http_modsecurity_pcre_malloc_done(ngx_pool_t *old_pool);
+#endif
 
 /* ngx_http_modsecurity_body_filter.c */
 ngx_int_t ngx_http_modsecurity_body_filter_init(void);

src/ngx_http_modsecurity_module.c

@@ -38,6 +38,7 @@ static void ngx_http_modsecurity_cleanup_rules(void *data);
  * https://github.com/openresty/lua-nginx-module/blob/master/src/ngx_http_lua_pcrefix.c
  */
 
+#if !(NGX_PCRE2)
 static void *(*old_pcre_malloc)(size_t);
 static void (*old_pcre_free)(void *ptr);
 static ngx_pool_t *ngx_http_modsec_pcre_pool = NULL;
@@ -103,6 +104,7 @@ ngx_http_modsecurity_pcre_malloc_done(ngx_pool_t *old_pool)
         pcre_free = old_pcre_free;
     }
 }
+#endif
 
 /*
  * ngx_string's are not null-terminated in common case, so we need to convert