Add PG11/master build, bump tools (#1588)

This build is allowed to fail and finish-fast is enabled, so there is
no negative impact on developers, yet we can now stay better abreast of
upcoming PostgreSQL changes.

The latest citus tools version also adds enable-depend to the flags in
our "custom PG" source-based builds which will result in fewer false
failures due to build caching behavior.

.travis.yml

@@ -14,10 +14,15 @@ env:
     # During pull request builds (not push builds), use custom-built PostgreSQL
     - USE_CUSTOM_PG="${TRAVIS_PULL_REQUEST_SHA}"
 matrix:
-    - PGVERSION=9.6
-    - PGVERSION=10
+  fast_finish: true
+  include:
+    - env: PGVERSION=9.6
+    - env: PGVERSION=10
+    - env: PGVERSION=11
+  allow_failures:
+    - env: PGVERSION=11
 before_install:
-  - git clone -b v0.6.4 --depth 1 https://github.com/citusdata/tools.git
+  - git clone -b v0.7.1 --depth 1 https://github.com/citusdata/tools.git
   - sudo make -C tools install
   - setup_apt
   - curl https://install.citusdata.com/community/deb.sh | sudo bash
@@ -27,7 +32,12 @@ install:
   - install_pg
   - install_custom_pg
   # download and install HLL manually, as custom builds won't satisfy deps
-  - apt-get download "postgresql-${PGVERSION}-hll=2.10.2.citus-1" && sudo dpkg --force-confold --force-confdef --force-all -i *hll*.deb
+  # only install if performing non-11 build
+  - |
+    if [ "${PGVERSION}" != "11" ]; then
+      apt-get download "postgresql-${PGVERSION}-hll=2.10.2.citus-1"
+      sudo dpkg --force-confold --force-confdef --force-all -i *hll*.deb
+    fi
 before_script: citus_indent --quiet --check
 script: CFLAGS=-Werror pg_travis_multi_test check
 after_success:

configure

@@ -2017,7 +2017,7 @@ if test -z "$version_num"; then
   as_fn_error $? "Could not detect PostgreSQL version from pg_config." "$LINENO" 5
 fi
 
-if test "$version_num" != '9.6' -a "$version_num" != '10'; then
+if test "$version_num" != '9.6' -a "$version_num" != '10' -a "$version_num" != '11'; then
    as_fn_error $? "Citus is not compatible with the detected PostgreSQL version ${version_num}." "$LINENO" 5
 else
    { $as_echo "$as_me:${as_lineno-$LINENO}: building against PostgreSQL $version_num" >&5

configure.in

@@ -59,7 +59,7 @@ if test -z "$version_num"; then
   AC_MSG_ERROR([Could not detect PostgreSQL version from pg_config.])
 fi
 
-if test "$version_num" != '9.6' -a "$version_num" != '10'; then
+if test "$version_num" != '9.6' -a "$version_num" != '10' -a "$version_num" != '11'; then
    AC_MSG_ERROR([Citus is not compatible with the detected PostgreSQL version ${version_num}.])
 else
    AC_MSG_NOTICE([building against PostgreSQL $version_num])