Revert "Revert "Merge branch 'master' into stable""

This reverts commit 33a29a0.

Author: Maxim Orlov

.travis.yml

@@ -1,5 +1,3 @@
-sudo: required
-
 language: c
 
 services:
@@ -18,13 +16,22 @@ notifications:
         on_failure: always
 
 env:
-    - PG_VERSION=11 LEVEL=nightmare
+    - PG_VERSION=13 LEVEL=nightmare
+    - PG_VERSION=13 LEVEL=hardcore
+    - PG_VERSION=13
+    # - PG_VERSION=12 LEVEL=nightmare
+    - PG_VERSION=12 LEVEL=hardcore
+    - PG_VERSION=12
+    # - PG_VERSION=11 LEVEL=nightmare
     - PG_VERSION=11 LEVEL=hardcore
     - PG_VERSION=11
     - PG_VERSION=10
     - PG_VERSION=9.6
     - PG_VERSION=9.5
 
+# XXX: consider fixing nightmare mode
 matrix:
     allow_failures:
         - env: PG_VERSION=11 LEVEL=nightmare
+        - env: PG_VERSION=12 LEVEL=nightmare
+        - env: PG_VERSION=13 LEVEL=nightmare

Dockerfile.tmpl

@@ -5,7 +5,7 @@ RUN apk add --no-cache \
 	openssl curl \
 	perl perl-ipc-run \
 	make musl-dev gcc bison flex coreutils \
-	zlib-dev libedit-dev \
+	zlib-dev libedit-dev linux-headers \
 	clang clang-analyzer;
 
 # Install fresh valgrind