dev-lib: fix failures on PHP 5.2 & 5.3

See WordPoints/dev-lib#225

.travis.yml

@@ -3,29 +3,57 @@
 language: php
 
 php:
+    - 7.2
     - 7.1
     - 7.0
     - 5.6
     - 5.5
     - 5.4
-    - 5.3
-    - 5.2
 
 env:
     - TRAVISCI_RUN=codesniff
     - TRAVISCI_RUN=phpunit WP_VERSION=develop
     - TRAVISCI_RUN=phpunit WP_VERSION=4.8
     - TRAVISCI_RUN=phpunit WP_VERSION=4.7
 
+dist: trusty
+
 sudo: false
 
+addons:
+  apt:
+    packages:
+      # Needed for `xmllint`.
+      - libxml2-utils
+
 matrix:
   include:
+    # Use Ubuntu Precise because Trusty doesn't support PHP 5.2 or 5.3.
+    - php: 5.3
+      dist: precise
+      env: TRAVISCI_RUN=phpunit WP_VERSION=develop
+    - php: 5.3
+      dist: precise
+      env: TRAVISCI_RUN=phpunit WP_VERSION=4.8
+    - php: 5.3
+      dist: precise
+      env: TRAVISCI_RUN=phpunit WP_VERSION=4.7
+    - php: 5.2
+      dist: precise
+      env: TRAVISCI_RUN=phpunit WP_VERSION=develop
+    - php: 5.2
+      dist: precise
+      env: TRAVISCI_RUN=phpunit WP_VERSION=4.8
+    - php: 5.2
+      dist: precise
+      env: TRAVISCI_RUN=phpunit WP_VERSION=4.7
     # Only run nightly against trunk.
     - php: nightly
       env: TRAVISCI_RUN=phpunit WP_VERSION=develop
   exclude:
     # The codesniff pass only needs to be run once.
+    - php: 7.2
+      env: TRAVISCI_RUN=codesniff
     - php: 7.0
       env: TRAVISCI_RUN=codesniff
     - php: 5.6
@@ -34,12 +62,9 @@ matrix:
       env: TRAVISCI_RUN=codesniff
     - php: 5.4
       env: TRAVISCI_RUN=codesniff
-    - php: 5.3
-      env: TRAVISCI_RUN=codesniff
-    - php: 5.2
-      env: TRAVISCI_RUN=codesniff
   allow_failures:
     - php: nightly
+    - php: 7.2
   fast_finish: true
 
 before_script: