Let user disable native colours with ./configure

configure.ac

@@ -451,6 +451,28 @@ fi
 
 AM_CONDITIONAL(BUILD_AV, test "x$BUILD_AV" = "xyes")
 
+# check for ncurses default colour capabilities
+NATIVE_COLOURS="yes"
+AC_ARG_ENABLE([native-colours],
+    [AC_HELP_STRING(
+        [--disable-native-colours], [use terminal-default fg/bg colours])
+    ],
+    [
+        if test "x$enableval" = "xno"; then
+            NATIVE_COLOURS="no"
+        elif test "x$enableval" = "xyes"; then
+            NATIVE_COLOURS="yes"
+        fi
+    ]
+)
+if test "x$NATIVE_COLOURS" = "xyes"; then
+    AC_CHECK_LIB([ncurses], [assume_default_colors],
+        [AC_DEFINE(
+            [TOXIC_NATIVE_COLOURS], [1], [use terminal-default fg/bg colours])
+        ],
+        [AC_MSG_WARN([curses library does not support native colours])]
+    )
+fi
 
 TOXIC_VERSION="$PACKAGE_VERSION"
 AC_PATH_PROG([GIT], [git], [no])

src/main.c

@@ -108,7 +108,7 @@ static void init_term(void)
     if (has_colors()) {
         short bg_color = COLOR_BLACK;
         start_color();
-#ifdef NCURSES_EXT_FUNCS
+#ifdef TOXIC_NATIVE_COLOURS
         if (assume_default_colors(-1,-1) == OK)
             bg_color = -1;
 #endif