diff --git a/Dockerfile-alpine.template b/Dockerfile-alpine.template
index 43e40974..1404280f 100644
--- a/Dockerfile-alpine.template
+++ b/Dockerfile-alpine.template
@@ -37,9 +37,9 @@ RUN mkdir -p $PHP_INI_DIR/conf.d
 # Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
 # Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
 # https://github.com/docker-library/php/issues/272
-ENV CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
-ENV CPPFLAGS="$CFLAGS"
-ENV LDFLAGS="-Wl,-O1 -Wl,--hash-style=both"
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
 
 ENV GPG_KEYS %%GPG_KEYS%%
 
@@ -89,6 +89,9 @@ RUN set -xe \
 		openssl-dev \
 		sqlite-dev \
 	\
+	&& export CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
 	&& docker-php-source extract \
 	&& cd /usr/src/php \
 	&& ./configure \
diff --git a/Dockerfile-debian.template b/Dockerfile-debian.template
index 2f4de9cd..896f1b17 100644
--- a/Dockerfile-debian.template
+++ b/Dockerfile-debian.template
@@ -32,9 +32,9 @@ RUN mkdir -p $PHP_INI_DIR/conf.d
 # Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
 # Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
 # https://github.com/docker-library/php/issues/272
-ENV CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
-ENV CPPFLAGS="$CFLAGS"
-ENV LDFLAGS="-Wl,-O1 -Wl,--hash-style=both"
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
 
 ENV GPG_KEYS %%GPG_KEYS%%
 
@@ -88,6 +88,9 @@ RUN set -xe \
 	" \
 	&& apt-get update && apt-get install -y $buildDeps --no-install-recommends && rm -rf /var/lib/apt/lists/* \
 	\
+	&& export CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
 	&& docker-php-source extract \
 	&& cd /usr/src/php \
 	&& ./configure \
diff --git a/docker-php-ext-configure b/docker-php-ext-configure
index 2a6f8394..93d31601 100755
--- a/docker-php-ext-configure
+++ b/docker-php-ext-configure
@@ -1,6 +1,12 @@
 #!/bin/sh
 set -e
 
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
 srcExists=
 if [ -d /usr/src/php ]; then
 	srcExists=1
diff --git a/docker-php-ext-install b/docker-php-ext-install
index 79df34e1..c0660230 100755
--- a/docker-php-ext-install
+++ b/docker-php-ext-install
@@ -1,6 +1,12 @@
 #!/bin/sh
 set -e
 
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
 srcExists=
 if [ -d /usr/src/php ]; then
 	srcExists=1