Make curses flags configurable

Makefile

@@ -8,19 +8,22 @@ INSTALL ?= install
 
 CFLAGS_OPTIMIZATION ?= -O3
 
-CFLAGS += -Wall -Wextra -Wno-unused-parameter
-CFLAGS += $(CFLAGS_OPTIMIZATION)
-
 ifeq ($(shell $(PKG_CONFIG) ncursesw && echo 1),1)
-	CFLAGS += $(shell $(PKG_CONFIG) --cflags ncursesw)
-	LDLIBS += $(shell $(PKG_CONFIG) --libs   ncursesw)
+	CFLAGS_CURSES ?= $(shell $(PKG_CONFIG) --cflags ncursesw)
+	LDLIBS_CURSES ?= $(shell $(PKG_CONFIG) --libs   ncursesw)
 else ifeq ($(shell $(PKG_CONFIG) ncurses && echo 1),1)
-	CFLAGS += $(shell $(PKG_CONFIG) --cflags ncurses)
-	LDLIBS += $(shell $(PKG_CONFIG) --libs   ncurses)
+	CFLAGS_CURSES ?= $(shell $(PKG_CONFIG) --cflags ncurses)
+	LDLIBS_CURSES ?= $(shell $(PKG_CONFIG) --libs   ncurses)
 else
-	LDLIBS += -lncurses
+	LDLIBS_CURSES ?= -lncurses
 endif
 
+CFLAGS += -Wall -Wextra -Wno-unused-parameter
+CFLAGS += $(CFLAGS_OPTIMIZATION)
+CFLAGS += $(CFLAGS_CURSES)
+
+LDLIBS += $(LDLIBS_CURSES)
+
 DISTFILES = src nnn.1 Makefile README.md LICENSE
 SRC = src/nnn.c
 BIN = nnn