diff --git a/config.m4 b/config.m4
index 915e7e9..803b4a0 100644
--- a/config.m4
+++ b/config.m4
@@ -2,8 +2,22 @@ PHP_ARG_ENABLE(pht, whether to enable pht support,
 [  --enable-pht           Enable pht support])
 
 if test "$PHP_PHT" != "no"; then
-  PHP_NEW_EXTENSION(pht, pht.c src/pht_copy.c src/pht_zend.c src/pht_entry.c src/pht_general.c src/ds/pht_queue.c src/ds/pht_hashtable.c src/ds/pht_vector.c src/classes/thread.c src/classes/threaded.c src/classes/runnable.c src/classes/queue.c src/classes/hashtable.c src/classes/vector.c src/classes/atomic_integer.c, $ext_shared,, -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1)
+    PHP_NEW_EXTENSION(pht, pht.c \
+        src/pht_copy.c \
+        src/pht_zend.c \
+        src/pht_entry.c \
+        src/pht_general.c \
+        src/ds/pht_queue.c \
+        src/ds/pht_hashtable.c \
+        src/ds/pht_vector.c \
+        src/classes/thread.c \
+        src/classes/threaded.c \
+        src/classes/runnable.c \
+        src/classes/queue.c \
+        src/classes/hashtable.c \
+        src/classes/vector.c \
+        src/classes/atomic_integer.c, $ext_shared,, -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1)
 
-  EXTRA_CFLAGS="$EXTRA_CFLAGS -std=gnu99"
-  PHP_SUBST(EXTRA_CFLAGS)
+    EXTRA_CFLAGS="$EXTRA_CFLAGS -std=gnu99"
+    PHP_SUBST(EXTRA_CFLAGS)
 fi