diff --git a/Makefile b/Makefile
index 2f0f843..5028ee4 100644
--- a/Makefile
+++ b/Makefile
@@ -10,14 +10,14 @@ INSTALLPATH = ${DESTDIR}${PREFIX}/bin
 MANPATH = ${DESTDIR}${PREFIX}/share/man/man1
 
 ifeq ($(shell sh -c 'which ncurses5-config>/dev/null 2>/dev/null && echo y'), y)
-	CFLAGS ?= -Wall -g $$(ncurses5-config --cflags)
-	LDFLAGS ?= $$(ncurses5-config --libs)
+	CFLAGS += -Wall -g $$(ncurses5-config --cflags)
+	LDFLAGS += $$(ncurses5-config --libs)
 else ifeq ($(shell sh -c 'which ncursesw5-config>/dev/null 2>/dev/null && echo y'), y)
-		CFLAGS ?= -Wall -g $$(ncursesw5-config --cflags)
-		LDFLAGS ?= $$(ncursesw5-config --libs)
+		CFLAGS += -Wall -g $$(ncursesw5-config --cflags)
+		LDFLAGS += $$(ncursesw5-config --libs)
 else
-	CFLAGS ?= -Wall -g $$(pkg-config --cflags ncurses)
-	LDFLAGS ?= $$(pkg-config --libs ncurses)
+	CFLAGS += -Wall -g $$(pkg-config --cflags ncurses)
+	LDFLAGS += $$(pkg-config --libs ncurses)
 endif
 
 tty-clock : ${SRC}