diff --git a/.travis.yml b/.travis.yml
index 05f1dd9..8526d46 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,9 @@
 sudo: false
 
+branches:
+  only:
+  - master
+
 services:
   - docker
 
diff --git a/data/supported-extensions b/data/supported-extensions
index 0815d67..1194b5b 100644
--- a/data/supported-extensions
+++ b/data/supported-extensions
@@ -10,6 +10,7 @@ exif 5.6 7.0 7.1 7.2 7.3
 gd 5.6 7.0 7.1 7.2 7.3
 gettext 5.6 7.0 7.1 7.2 7.3
 gmp 5.6 7.0 7.1 7.2 7.3
+igbinary 5.6 7.0 7.1 7.2 7.3
 imagick 5.6 7.0 7.1 7.2 7.3
 imap 5.6 7.0 7.1 7.2 7.3
 interbase 5.6 7.0 7.1 7.2 7.3
diff --git a/install-php-extensions b/install-php-extensions
index 0b2290e..7cc801e 100755
--- a/install-php-extensions
+++ b/install-php-extensions
@@ -418,12 +418,13 @@ getPackageSource () {
 #   $1: the handle of the PHP module
 #   $2: the URL of the module source code
 #   $3: the options of the configure command
+#   $4: the value of CFLAGS
 installModuleFromSource () {
 	printf '### INSTALLING MODULE %s FROM SOURCE CODE ###\n' "${1}"
 	installModuleFromSource_dir="$(getPackageSource "${2}")"
 	cd "${installModuleFromSource_dir}"
 	phpize
-	./configure ${3}
+	./configure ${3} CFLAGS="${4:-}"
 	make -j$(nproc) install
 	cd --
 	docker-php-ext-enable "${1}"
@@ -546,6 +547,7 @@ then
 		else
 			MODULE_SOURCE=''
 			MODULE_SOURCE_CONFIGOPTIONS=''
+			MODULE_SOURCE_CFLAGS=''
 			case "${PHP_MODULE_TO_INSTALL}" in
 				cmark)
 					MODULE_SOURCE=https://github.com/krakjoe/cmark/archive/v1.0.0.tar.gz
@@ -554,10 +556,19 @@ then
 					cd -
 					MODULE_SOURCE_CONFIGOPTIONS=--with-cmark
 					;;
+				igbinary)
+					if test ${PHP_MAJMIN_VERSION} -lt 700; then
+						MODULE_SOURCE="https://github.com/igbinary/igbinary/archive/2.0.8.tar.gz"
+					else
+						MODULE_SOURCE="https://github.com/igbinary/igbinary/archive/3.0.1.tar.gz"
+					fi
+					MODULE_SOURCE_CONFIGOPTIONS=--enable-igbinary
+					MODULE_SOURCE_CFLAGS='-O2 -g'
+					;;
 			esac
 			if test -n "${MODULE_SOURCE}"
 			then
-				installModuleFromSource "${PHP_MODULE_TO_INSTALL}" "${MODULE_SOURCE}" "${MODULE_SOURCE_CONFIGOPTIONS}"
+				installModuleFromSource "${PHP_MODULE_TO_INSTALL}" "${MODULE_SOURCE}" "${MODULE_SOURCE_CONFIGOPTIONS}" "${MODULE_SOURCE_CFLAGS}"
 			else
 				installPECLModule ${PHP_MAJMIN_VERSION} "${PHP_MODULE_TO_INSTALL}"
 			fi