Fix boolean logic in Makefile for ncurses detection

- Corrected logical error in Makefile when checking for ncurses existence.

This change ensures the correct boolean output from pkg-config by replacing a
duplicate echo true statement with the correct echo false. This improves the
Makefile's reliability in detecting ncurses and is crucial for avoiding false
positives that could lead to build errors.

Makefile

@@ -23,7 +23,7 @@ ifndef ($(OS))
 endif
 
 ifeq ($(PKG_CONFIG_FOUND),true)
-  CURSES_FOUND := $(shell pkg-config --exists ncurses && echo true || echo true)
+  CURSES_FOUND := $(shell pkg-config --exists ncurses && echo true || echo false)
   CURSES_LIBS  := $(shell pkg-config --libs ncurses)
 else
   CURSES_FOUND := false