From: Michael R. Crusoe <crusoe@debian.org>
Subject: Use CPPFLAGS, CFLAGS, and LDFLAGS
Forwarded: https://github.com/biocore/unifrac-binaries/pull/46

--- unifrac-tools.orig/combined/Makefile
+++ unifrac-tools/combined/Makefile
@@ -13,10 +13,10 @@
 endif
 
 libssu.o: libssu.c
-	$(CC) -c libssu.c -fPIC
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c libssu.c -fPIC
 
 libssu.so: libssu.o
-	$(CC) -shared -o libssu.so libssu.o -fPIC -ldl
+	$(CC) -shared -o libssu.so libssu.o -fPIC -ldl $(LDFLAGS)
 
 install: libssu.so
 	rm -f ${PREFIX}/lib//libssu.so; cp libssu.so ${PREFIX}/lib/
--- unifrac-tools.orig/test/Makefile
+++ unifrac-tools/test/Makefile
@@ -1,8 +1,5 @@
 .PHONY: test_binaries test
 
-CFLAGS := 
-LDFLAGS :=
-
 ifeq ($(PREFIX),)
 	PREFIX := $(CONDA_PREFIX)
 endif
@@ -13,7 +10,7 @@
 test_binaries: capi_test
 
 capi_test: capi_test.c
-	$(CC) -std=c99 -O0 -g capi_test.c -I../src -lssu -L${PREFIX}/lib -Wl,-rpath,${PREFIX}/lib -o capi_test
+	$(CC) $(CFLAGS) -std=c99 -O0 -g capi_test.c -I../src -lssu -L${PREFIX}/lib -Wl,-rpath,${PREFIX}/lib $(LDFLAGS) -o capi_test
 
 clean:
 	-rm -f *.o capi_test
