Test php 7.0 and 7.1 on Travis

- php-7.1 set as failing for now due to one broken example (references)
- Look for php 7.1 in configure.ac.

.travis.yml

@@ -94,6 +94,16 @@ matrix:
       env: SWIGLANG=php5
       sudo: required
       dist: trusty
+    - compiler: gcc
+      os: linux
+      env: SWIGLANG=php VER=7.0
+      sudo: required
+      dist: trusty
+    - compiler: gcc
+      os: linux
+      env: SWIGLANG=php VER=7.1
+      sudo: required
+      dist: trusty
     - compiler: gcc
       os: linux
       env: SWIGLANG=python VER=2.4
@@ -276,6 +286,12 @@ matrix:
       env: SWIGLANG=python SWIG_FEATURES=-O
       sudo: required
       dist: trusty
+    # php7.1 nearly working
+    - compiler: gcc
+      os: linux
+      env: SWIGLANG=php VER=7.1
+      sudo: required
+      dist: trusty
 before_install:
   - date -u
   - uname -a

Tools/travis-linux-install.sh

@@ -74,6 +74,11 @@ case "$SWIGLANG" in
 	"php5")
 		sudo apt-get -qq install php5-cli php5-dev
 		;;
+	"php")
+		sudo add-apt-repository -y ppa:ondrej/php
+		sudo apt-get -qq update
+		sudo apt-get -qq install php$VER-cli php$VER-dev
+		;;
 	"python")
 		sudo apt-get -qq install pep8
 		if [[ "$PY3" ]]; then

configure.ac

@@ -1960,7 +1960,7 @@ if test x"${PHPBIN}" = xno; then
     PHP=
 else
     if test "x$PHPBIN" = xyes; then
-      AC_CHECK_PROGS(PHP, [php7.0 php])
+      AC_CHECK_PROGS(PHP, [php7.1 php7.0 php])
     else
       PHP=$PHPBIN
     fi