diff --git a/common.mk b/common.mk
index 86585e59..fed147b8 100644
--- a/common.mk
+++ b/common.mk
@@ -1,5 +1,6 @@
 UNAME=$(shell uname)
 DEBUG=1
+COVERAGE=0
 INSTALL=install
 PREFIX=/usr
 ifeq ($(PREFIX),/usr)
@@ -97,6 +98,11 @@ CFLAGS += -O2
 CFLAGS += -freorder-blocks-and-partition
 endif
 
+ifeq ($(COVERAGE),1)
+CFLAGS += -fprofile-arcs -ftest-coverage
+LDFLAGS += -lgcov
+endif
+
 # Don’t print command lines which are run
 .SILENT: