Fix makefile targets. Remove unnecessary warnings.

Makefile

@@ -1,30 +1,26 @@
 CC      ?= clang
-CFLAGS  += -g -Wall -Wextra
+CFLAGS  += -Wno-visibility -Wno-incompatible-pointer-types -Wall -Wextra -O2 -DINVERT_COLORS -DVT100
 LFLAGS  +=
-DEFINES := -DINVERT_COLORS -DVT100 $(shell pkg-config --cflags sdl2)
 
 PROGRAM := 2048
 C_FILES := $(wildcard src/*.c)
-O_FILES := $(addprefix obj/, $(notdir $(C_FILES:.c=.o)))
-FILTERED_O_FILES := $(filter-out obj/gfx%.o obj/merge%.o, $(O_FILES))
+MERGE_FILE := src/merge_std.c
+FILTERED_C_FILES := $(filter-out src/gfx%.c src/merge%.c, $(C_FILES))
 
-all: curses
+all: terminal
 
-curses: $(O_FILES)
-	$(CC) $(FILTERED_O_FILES) obj/merge_std.o obj/gfx_curses.o -o $(PROGRAM) -lcurses
+curses: $(FILTERED_C_FILES) src/gfx_curses.c
+	$(CC) $(CFLAGS) $(FILTERED_C_FILES) $(MERGE_FILE) src/gfx_curses.c -o $(PROGRAM) -lcurses
 
-vt100: $(O_FILES)
-	$(CC) $(FILTERED_O_FILES) obj/merge_std.o obj/gfx_terminal.o -o $(PROGRAM)
+terminal: $(FILTERED_C_FILES) src/gfx_terminal.c
+	$(CC) $(CFLAGS) $(FILTERED_C_FILES) $(MERGE_FILE) src/gfx_terminal.c -o $(PROGRAM)
 
-sdl: $(O_FILES)
-	$(CC) $(FILTERED_O_FILES) obj/merge_std.o obj/gfx_sdl.o -o $(PROGRAM) -lSDL2 -lSDL2_ttf
-
-obj/%.o: src/%.c
-	$(CC) $(DEFINES) $(CFLAGS) -c -o $@ $<
+sdl: $(FILTERED_C_FILES) src/gfx_sdl.c
+	$(CC) $(CFLAGS) $(FILTERED_C_FILES) $(MERGE_FILE) src/gfx_sdl.c -o $(PROGRAM) $(shell pkg-config --cflags sdl2) -lSDL2 -lSDL2_ttf
 
 remake: clean all
 
 clean:
-	rm -f $(O_FILES) $(PROGRAM)
+	rm -f $(PROGRAM)
 
 .PHONY: clean remake

README.md

@@ -13,7 +13,20 @@ create a .c file which implements all the functions in gfx.h and add a Makefile
     git clone https://github.com/Tiehuis/2048-cli.git
     make
 
-You can also easily install this on el >= 5 (CentOS, RedHat Enterprise Linux,
+By default, termios.h is expected to be present for the standard terminal version, and
+a VT100 compatible terminal is being used. If a VT100 terminal is not available, simply
+alter the makefile and remove the '-DVT100' flag. Compiling with ncurses requires
+the development libraries for it, and likewise for using SDL2.
+
+On an ubuntu/debian machine for example, these can be obtained via
+
+    apt-get install libncurses5-dev
+    apt-get install libsdl2-dev libsdl2-ttf-dev
+
+Note: The sdl version is largely to demonstrate plugging in an alternative
+graphics frontend, and is likely not wanted. The ncurses version is recommended.
+
+You can also also easily install this on el >= 5 (CentOS, RedHat Enterprise Linux,
 Scientific Linux, Oracle) and Fedora >= 19 using the package-manager:
 
     sudo yum install 2048-cli[-nocurses]

src/ai.c

@@ -1,3 +1,4 @@
+#include <stdlib.h>
 #include "ai.h"
 #include "engine.h"
 #include "gfx.h"
@@ -6,6 +7,7 @@ const char moves[] = {'w', 'a', 's', 'd'};
 
 int ai_move(struct gamestate *g)
 {
+    /* Ensure srand is called somewhere prior */
     if (g->opts->interactive) gfx_sleep(50);
     return moves[rand() % 4];
 }

src/gfx_sdl.c

@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <SDL.h>
 #include <SDL_ttf.h>
+#include "merge.h"
 #include "gfx.h"
 
 /* Side length of a 'pixel' in pixels */

src/gfx_terminal.c

@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <termios.h>
 #include <unistd.h>
+#include "merge.h"
 #include "gfx.h"
 
 #define iterate(n, expression)\
@@ -16,7 +17,10 @@ struct gfx_state {
 
 struct gfx_state* gfx_init(struct gamestate *g)
 {
+    (void) g;
+
     struct gfx_state *s = malloc(sizeof(struct gfx_state));
+    if (!s) return NULL;
     tcgetattr(STDIN_FILENO, &s->oldt);
     s->newt = s->oldt;
     s->newt.c_lflag &= ~(ICANON | ECHO);
@@ -26,6 +30,8 @@ struct gfx_state* gfx_init(struct gamestate *g)
 
 void gfx_draw(struct gfx_state *s, struct gamestate *g)
 {
+    (void) s;
+
 #ifdef VT100
     printf("\033[2J\033[H");
 #endif
@@ -57,6 +63,7 @@ void gfx_draw(struct gfx_state *s, struct gamestate *g)
 
 int gfx_getch(struct gfx_state *s)
 {
+    (void) s;
     return getchar();
 }
 
@@ -65,8 +72,8 @@ void gfx_sleep(int ms)
     usleep(ms * 1000);
 }
 
-void gfx_destroy(struct gfx_state *t)
+void gfx_destroy(struct gfx_state *s)
 {
-    tcsetattr(STDIN_FILENO, TCSANOW, &t->oldt);
-    free(t);
+    tcsetattr(STDIN_FILENO, TCSANOW, &s->oldt);
+    free(s);
 }