--- a/Makefile
+++ b/Makefile
@@ -52,8 +52,8 @@
 INSTBIN=mbconv${EXT}
 
 DEBUG=
-CF=${DEBUG} -O2 -Wall -fpic -I.
-LF=-shared -Wl,-soname,${DEST}.so.${VER}.${RELEASE}
+CF=${DEBUG} -O2 -Wall -fpic -I. ${CFLAGS}
+LF=-shared -Wl,-soname,${DEST}.so.${VER}.${RELEASE} ${LDFLAGS}
 CC=gcc
 CPP=gcc -E
 LD=gcc
@@ -72,7 +72,7 @@
 all: ${INSTLIBA} mbconv mbconv.man
 
 mbconv: mbconv.c ${ALL}
-	${CC} ${CF} -o $@ $< -L. -lmoe
+	${CC} ${CF} ${LDFLAGS} -o $@ $< -L. -lmoe
 
 
 ${DEST}.so: ${DEST}.so.${VER}.${RELEASE}
@@ -116,7 +116,7 @@
 	./mk_btri <$< >$@-new && mv $@-new $@
 
 mk_btri: btri.c btri.h altmalloc.o
-	${CC} ${CF} -DMAIN -o $@ $< altmalloc.o
+	${CC} ${CF} ${LDFLAGS} -DMAIN -o $@ $< altmalloc.o
 
 mbconv.man: mbconv.pod
 	pod2man --section=${MANSECT} --center=' ' $< >$@
--- a/altmalloc.c
+++ b/altmalloc.c
@@ -1,3 +1,5 @@
+#include <string.h>
+
 #include "altmalloc.h"
 
 alt_allocater_t alt_malloc = malloc;