diff --git a/configure.ac b/configure.ac
index 7bfae5e4..b4e37b9d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,12 +1,11 @@
 #                                               -*- Autoconf -*-
 # Process this file with autoconf to produce a configure script.
 
-AC_PREREQ([2.69])
 AC_INIT([libpostal], [0.1])
 AM_INIT_AUTOMAKE([foreign subdir-objects])
-LT_PREREQ([2.2])
-LT_INIT([shared])
 AC_CONFIG_SRCDIR([src])
+LT_INIT([shared])
+
 AC_CONFIG_HEADERS([config.h])
 
 # Checks for programs.
diff --git a/src/Makefile.LastModified b/src/Makefile.LastModified
new file mode 100644
index 00000000..7868e5d2
--- /dev/null
+++ b/src/Makefile.LastModified
@@ -0,0 +1,5 @@
+ifeq ("$(wildcard $(LIBPOSTAL_DATA_LAST_UPDATED))", "")
+    LAST_MODIFIED_DATE = $(EPOCH_DATE)
+else
+    LAST_MODIFIED_DATE = $(call get_last_modified,$(LIBPOSTAL_DATA_LAST_UPDATED))
+endif
\ No newline at end of file
diff --git a/src/Makefile.am b/src/Makefile.am
index 0b6c5ec3..5dd93e5f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,6 +5,7 @@ CFLAGS_O0 = $(CFLAGS_BASE) -O0
 CFLAGS_O1 = $(CFLAGS_BASE) -O1
 CFLAGS_O2 = $(CFLAGS_BASE) -O2
 CFLAGS_O3 = $(CFLAGS_BASE) -O3
+DEFAULT_INCLUDES=-I..
 
 CFLAGS = $(CFLAGS_BASE) -DLIBPOSTAL_DATA_DIR='"$(LIBPOSTAL_DATA_DIR)"'
 
@@ -30,22 +31,19 @@ EPOCH_DATE = Jan  1 00:00:00 1970
 LIBPOSTAL_DATA_DIR = $(datadir)/libpostal/
 LIBPOSTAL_DATA_LAST_UPDATED = $(LIBPOSTAL_DATA_DIR)libpostal_data_last_updated
 
-LAST_MODIFIED = $(EPOCH_DATE)
-
 if HAVE_DATE_STAT
 USE_DATE_STAT = 1
 
-define set_last_modified
-$(eval LAST_MODIFIED := $(shell date -d "@$(shell cat $1)"))
+define get_last_modified
+$(shell date -d "@$$(shell cat $1)")
 endef
 
 else
 if HAVE_STAT
-
 USE_STAT = 1
 
-define set_last_modified
-$(eval LAST_MODIFIED := $(shell date -r "$(shell cat $1)"))
+define get_last_modified
+$(shell date -r "$(shell cat $1)")
 endef
 
 else
@@ -54,27 +52,19 @@ endif
 
 endif
 
+$(eval include $(srcdir)/Makefile.LastModified)
 
 libpostal_data_mkdir:
 	mkdir -p $(LIBPOSTAL_DATA_DIR)
 
-libpostal_data_last_updated: libpostal_data_mkdir
-	if [ -e $(LIBPOSTAL_DATA_LAST_UPDATED) ]; then						\
-		$(call set_last_modified,$(LIBPOSTAL_DATA_LAST_UPDATED))		\
-		echo "LAST_MODIFIED=$(LAST_MODIFIED)";							\
-	else																\
-		echo "LAST_MODIFIED=$(LAST_MODIFIED)";							\
-	fi;
-
-
-libpostal_data.tar.gz: libpostal_data_mkdir libpostal_data_last_updated
-	if [ `curl $(LIBPOSTAL_S3_BUCKET_URL)/$(LIBPOSTAL_DATA_FILE) -z "$(LAST_MODIFIED)" --silent --remote-time -o $(LIBPOSTAL_DATA_DIR)$(LIBPOSTAL_DATA_FILE) -w %{http_code}` = "200" ]; then		\
+libpostal_data.tar.gz: libpostal_data_mkdir
+	if [ `curl $(LIBPOSTAL_S3_BUCKET_URL)/$(LIBPOSTAL_DATA_FILE) -z "$(LAST_MODIFIED_DATE)" --silent --remote-time -o $(LIBPOSTAL_DATA_DIR)$(LIBPOSTAL_DATA_FILE) -w %{http_code}` = "200" ]; then	\
 		if [ "x$(USE_DATE_STAT)" != "x" ]; then																																						\
 			echo $$(date -d"$$(date -d "@$$(date -r $(LIBPOSTAL_DATA_DIR)$(LIBPOSTAL_DATA_FILE)) +%s") + 1 second" +%s) > $(LIBPOSTAL_DATA_LAST_UPDATED);											\
 		elif [ "x$(USE_STAT)" != "x" ]; then																																						\
 			echo $$(date -r $$(stat -f %m $(LIBPOSTAL_DATA_DIR)$(LIBPOSTAL_DATA_FILE)) -v+1S +%s) > $(LIBPOSTAL_DATA_LAST_UPDATED);																	\
 		fi;																																															\
-		tar -xvzf $(LIBPOSTAL_DATA_DIR)$(LIBPOSTAL_DATA_FILE) -C $(LIBPOSTAL_DATA_DIR); 																									\
+		tar -xvzf $(LIBPOSTAL_DATA_DIR)$(LIBPOSTAL_DATA_FILE) -C $(LIBPOSTAL_DATA_DIR); 																											\
 	fi;
 
 address_dictionary_builder: address_dictionary_builder.c