diff --git a/.gitignore b/.gitignore
index cadaacd..e607722 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,5 @@
 /build/
-/release/
\ No newline at end of file
+/release/
+*.mk
+*.user
+*.d
diff --git a/Makefile b/Makefile
index 5f60792..0ab6c30 100644
--- a/Makefile
+++ b/Makefile
@@ -17,6 +17,54 @@
 # - Windows                                             #
 # ----------------------------------------------------- #
 
+# Variables
+# ---------
+# ASAN
+#   Builds with address sanitizer, includes DEBUG.
+# DEBUG
+#   Builds a debug build, forces -O0 and adds debug symbols.
+# MINGW_CHOST
+#   If you use mingw this can specify architecture.
+#   Available values:
+#   x86_64-w64-mingw32 -> indicates x86_64
+#   i686-w64-mingw32   -> indicates i386
+# QUIET
+#   If defined, "===> CC ..." lines are silenced.
+# SOURCE_DATE_EPOCH
+#   For reproduceable builds, look here for details:
+#   https://reproducible-builds.org/specs/source-date-epoch/
+#   If set, adds a BUILD_DATE define to CFLAGS.
+# UBSAN
+#   Builds with undefined behavior sanitizer.includes DEBUG.
+# VERBOSE
+#   Prints full compile, linker and misc commands.
+# WERR
+#   Treat compiler warnings as errors.
+#   If defined, -Werror is added to compiler flags.
+# ----------
+
+# User configurable options
+# -------------------------
+
+# CONFIG_FILE
+# This is an optional configuration file, it'll be used in
+# case of presence.
+CONFIG_FILE:=config.mk
+
+# ----------
+
+# In case of a configuration file being present, we'll just use it
+ifeq ($(wildcard $(CONFIG_FILE)), $(CONFIG_FILE))
+include $(CONFIG_FILE)
+endif
+
+# Normalize QUIET value to either "x" or ""
+ifdef QUIET
+	override QUIET := "x"
+else
+	override QUIET := ""
+endif
+
 # Detect the OS
 ifdef SystemRoot
 YQ2_OSTYPE ?= Windows
@@ -71,24 +119,58 @@ else
 COMPILER := unknown
 endif
 
+# ASAN includes DEBUG
+ifdef ASAN
+DEBUG=1
+endif
+
+# UBSAN includes DEBUG
+ifdef UBSAN
+DEBUG=1
+endif
+
+# ----------
+
+# Set up build and bin output directories
+
+# Root dir names
+override BINROOT :=
+override BUILDROOT := build
+
+override BINDIR := $(BINROOT)release
+override BUILDDIR := $(BUILDROOT)
+
 # ----------
 
 # Base CFLAGS. These may be overridden by the environment.
 # Highest supported optimizations are -O2, higher levels
 # will likely break this crappy code.
 ifdef DEBUG
-CFLAGS ?= -O0 -g -Wall -pipe
+CFLAGS ?= -O0 -g -Wall -pipe -DDEBUG
+ifdef ASAN
+override CFLAGS += -fsanitize=address -DUSE_SANITIZER
+endif
+ifdef UBSAN
+override CFLAGS += -fsanitize=undefined -DUSE_SANITIZER
+endif
 else
 CFLAGS ?= -O2 -Wall -pipe -fomit-frame-pointer
 endif
 
+# Optionally treat warnings as errors
+ifdef WERR
+override CFLAGS += -Werror
+endif
+
 # Always needed are:
 #  -fno-strict-aliasing since the source doesn't comply
 #   with strict aliasing rules and it's next to impossible
 #   to get it there...
 #  -fwrapv for defined integer wrapping. MSVC6 did this
 #   and the game code requires it.
-override CFLAGS += -fno-strict-aliasing -fwrapv
+#  -fvisibility=hidden to keep symbols hidden. This is
+#   mostly best practice and not really necessary.
+override CFLAGS += -fno-strict-aliasing -fwrapv -fvisibility=hidden
 
 # -MMD to generate header dependencies. Unsupported by
 #  the Clang shipped with OS X.
@@ -124,8 +206,6 @@ override CFLAGS += -DYQ2OSTYPE=\"$(YQ2_OSTYPE)\" -DYQ2ARCH=\"$(YQ2_ARCH)\"
 
 # ----------
 
-# For reproduceable builds, look here for details:
-# https://reproducible-builds.org/specs/source-date-epoch/
 ifdef SOURCE_DATE_EPOCH
 CFLAGS += -DBUILD_DATE=\"$(shell date --utc --date="@${SOURCE_DATE_EPOCH}" +"%b %_d %Y" | sed -e 's/ /\\ /g')\"
 endif
@@ -154,7 +234,17 @@ LDFLAGS ?=
 # It's a shared library.
 override LDFLAGS += -shared
 
-# Required libaries
+# Link address sanitizer if requested.
+ifdef ASAN
+override LDFLAGS += -fsanitize=address
+endif
+
+# Link undefined behavior sanitizer if requested.
+ifdef UBSAN
+override LDFLAGS += -fsanitize=undefined
+endif
+
+# Required libraries
 ifeq ($(YQ2_OSTYPE), Darwin)
 override LDFLAGS += -arch $(YQ2_ARCH)
 else ifeq ($(YQ2_OSTYPE), Windows)
@@ -163,6 +253,19 @@ else
 override LDFLAGS += -lm
 endif
 
+# ASAN and UBSAN must not be linked
+# with --no-undefined. OSX and OpenBSD
+# don't support it at all.
+ifndef ASAN
+ifndef UBSAN
+ifneq ($(YQ2_OSTYPE), Darwin)
+ifneq ($(YQ2_OSTYPE), OpenBSD)
+override LDFLAGS += -Wl,--no-undefined
+endif
+endif
+endif
+endif
+
 # ----------
 
 # Builds everything
@@ -197,24 +300,26 @@ clean:
 ifeq ($(YQ2_OSTYPE), Windows)
 xatrix:
 	@echo "===> Building game.dll"
-	${Q}mkdir -p release
-	${MAKE} release/game.dll
+	${Q}mkdir -p $(BINDIR)
+	${MAKE} $(BINDIR)/game.dll
 else ifeq ($(YQ2_OSTYPE), Darwin)
 xatrix:
 	@echo "===> Building game.dylib"
-	${Q}mkdir -p release
-	$(MAKE) release/game.dylib
+	${Q}mkdir -p $(BINDIR)
+	$(MAKE) $(BINDIR)/game.dylib
 else
 xatrix:
 	@echo "===> Building game.so"
-	${Q}mkdir -p release
-	$(MAKE) release/game.so
+	${Q}mkdir -p $(BINDIR)
+	$(MAKE) $(BINDIR)/game.so
 
-release/game.so : CFLAGS += -fPIC
+$(BINDIR)/game.so : CFLAGS += -fPIC
 endif
 
-build/%.o: %.c
-	@echo "===> CC $<"
+$(BUILDDIR)/%.o: %.c
+	@if [ -z $(QUIET) ]; then\
+		echo "===> CC $<";\
+	fi
 	${Q}mkdir -p $(@D)
 	${Q}$(CC) -c $(CFLAGS) -o $@ $<
 
@@ -277,7 +382,7 @@ XATRIX_OBJS_ = \
 # ----------
 
 # Rewrite paths to our object directory
-XATRIX_OBJS = $(patsubst %,build/%,$(XATRIX_OBJS_))
+XATRIX_OBJS = $(patsubst %,$(BUILDDIR)/%,$(XATRIX_OBJS_))
 
 # ----------
 
@@ -292,15 +397,15 @@ XATRIX_DEPS= $(XATRIX_OBJS:.o=.d)
 # ----------
 
 ifeq ($(YQ2_OSTYPE), Windows)
-release/game.dll : $(XATRIX_OBJS)
+$(BINDIR)/game.dll : $(XATRIX_OBJS)
 	@echo "===> LD $@"
 	${Q}$(CC) -o $@ $(XATRIX_OBJS) $(LDFLAGS)
 else ifeq ($(YQ2_OSTYPE), Darwin)
-release/game.dylib : $(XATRIX_OBJS)
+$(BINDIR)/game.dylib : $(XATRIX_OBJS)
 	@echo "===> LD $@"
 	${Q}$(CC) -o $@ $(XATRIX_OBJS) $(LDFLAGS)
 else
-release/game.so : $(XATRIX_OBJS)
+$(BINDIR)/game.so : $(XATRIX_OBJS)
 	@echo "===> LD $@"
 	${Q}$(CC) -o $@ $(XATRIX_OBJS) $(LDFLAGS)
 endif