standardize on c99

Makefile

@@ -1,11 +1,12 @@
 CC=gcc
-CFLAGS=-lncursesw
+CFLAGS=-std=c99 -pedantic -Wall -Wextra
+LIBS=-lncursesw
 EXECUTABLE=bbs
 
 all: make
 
 make:
-	$(CC) $(CFLAGS) bbs.c -o $(EXECUTABLE)
+	$(CC) $(CFLAGS) $(LIBS) bbs.c -o $(EXECUTABLE)
 
 run:
 	./$(EXECUTABLE)

README.md

@@ -6,6 +6,8 @@ This is a simple bbs program written in c. The way it is meant to work is that a
 
 The only dependency is `ncurses`. The makefile asks for `-lncursesw` but unicode is not yet used, so `-lncurses` should be fine. `ncurses` is almost guaranteed preinstalled on your system.
 
+The program is standardized on c99. It should run fine on c89, but there will be warnings. You'll have to edit the makefile to request c89 from `gcc`.
+
 To build, run `make`. It will drop an executable named `bbs` in the current folder.
 
 The makefile has the additional command `make run`, which just launches the program after compilation.

bbs.c

@@ -46,7 +46,7 @@ void draw_screen (struct Screen *screen) {
     box(screen->win, 0, 0);
 
     mvwprintw(screen->win, 0, 1, " %s ", screen->name);
-};
+}
 
 int main() {
 
@@ -69,7 +69,7 @@ int main() {
 
     getmaxyx(stdscr, terminal_height, terminal_width);
 
-    int screen_before_error = HOME;
+    unsigned int screen_before_error = HOME;
 
     enum ActiveScreen active_screen = HOME;
     struct Screen home = {