Add Makefile, update build instructions

.gitignore

@@ -0,0 +1,2 @@
+build/*
+lite

Makefile

@@ -0,0 +1,56 @@
+PREFIX ?= $(HOME)/.local
+
+OBJ_DIR ?= $(shell pwd)/build
+SRC_DIR := $(shell pwd)/src
+
+SRC_EXT := c
+OBJ_EXT := o
+
+SRCS := $(shell find $(SRC_DIR) -name *.$(SRC_EXT))
+
+SOURCES := $(foreach sname, $(SRCS), $(abspath $(sname)))
+OBJECTS := $(patsubst $(SRC_DIR)/%.$(SRC_EXT), $(OBJ_DIR)/%.$(OBJ_EXT), $(SOURCES))
+
+CFLAGS ?=
+LDLAGS ?=
+
+CFLAGS +=-Wall -O3 -g -std=gnu11 -fno-strict-aliasing -Isrc
+LDFLAGS +=-lSDL2 -lm -ldl
+
+ifeq ($(OS),Windows_NT)
+  TARGET ?= lite.exe
+  CC := x86_64-w64-mingw32-gcc
+  CFLAGS += -DLUA_USE_POPEN -Iwinlib/SDL2-2.0.10/x86_64-w64-mingw32/include
+  LDFLAGS += -Lwinlib/SDL2-2.0.10/x86_64-w64-mingw32/lib -lmingw32 -lSDL2main -mwindows res.res
+	x86_64-w64-mingw32-windres res.rc -O coff -o res.res
+else
+  TARGET ?= lite
+  CC := gcc
+  UNAME := $(shell uname -s)
+  ifeq ($(UNAME_S),Linux)
+    CFLAGS +=-DLUA_USE_POSIX -fPIC -DLUA_COMPAT_ALL
+  endif
+endif
+
+all: $(TARGET)
+
+$(TARGET): $(OBJECTS)
+	$(CC) $^ -o $@ $(LDFLAGS)
+
+$(OBJ_DIR)/%$(OBJ_EXT): $(SRC_DIR)/%$(SRC_EXT)
+	@mkdir -p $(dir $@)
+	$(CC) -c $(CFLAGS) $< -o $@
+
+clean:
+	-rm -f $(OBJECTS) $(TARGET)
+
+.PHONY: clean
+
+install: all
+	@echo Installing to $(PREFIX) ...
+	@mkdir -p $(PREFIX)/bin/
+	@cp -fp $(TARGET) $(PREFIX)/bin/
+	@mkdir -p $(PREFIX)/bin/data
+	@echo Copying lua files to $(PREFIX)/bin/data
+	@cp -r data/* $(PREFIX)/bin/data/
+	@echo Complete.

README.md

@@ -24,8 +24,25 @@ The editor can be customized by making changes to the
 [user module](data/user/init.lua).
 
 ## Building
-You can build the project yourself on Linux using the `build.sh` script
-or on Windows using the `build.bat` script *([MinGW](https://nuwen.net/mingw.html) is required)*.
+
+### Linux
+
+You can build the project yourself on Linux with following prerequisites:
+
+ * GCC
+ * Simple DirectMedia Layer development files
+
+#### Debian/Ubuntu
+
+```
+sudo apt install libsdl2-dev gcc make
+make
+sudo make install PREFIX=/usr/local
+```
+
+### Windows
+
+Using the `build.bat` script *([MinGW](https://nuwen.net/mingw.html) is required)*.
 Note that the project does not need to be rebuilt if you are only making changes
 to the Lua portion of the code.