diff --git a/GNUbase.mk b/GNUbase.mk
deleted file mode 100644
index c3bf012d..00000000
--- a/GNUbase.mk
+++ /dev/null
@@ -1,66 +0,0 @@
-# 22 april 2015
-
-OUTBASE = new
-OUTDIR = out
-OBJDIR = .obj
-
-IDLFILES = \
-	$(baseIDLFILES)
-
-xHFILES = \
-	$(baseHFILES)
-
-OFILES = \
-	$(baseCFILES:%.c=$(OBJDIR)/%.o) \
-	$(baseMFILES:%.m=$(OBJDIR)/%.o) \
-	$(baseRCFILES:%.rc=$(OBJDIR)/%.o)
-
-xCFLAGS = \
-	-g \
-	-Wall -Wextra \
-	-Wno-unused-parameter \
-	-Wno-switch \
-	--std=c99 \
-	$(CFLAGS) \
-	$(archmflag) \
-	$(baseCFLAGS)
-
-# windres doesn't support -m
-xRCFLAGS = \
-	$(RCFLAGS) \
-	$(baseRCFLAGS)
-
-xLDFLAGS = \
-	-g \
-	$(LDFLAGS) \
-	$(archmflag) \
-	$(baseLDFLAGS)
-
-OUT = $(OUTDIR)/$(OUTBASE)$(baseSUFFIX)
-
-$(OUT): $(OFILES) | $(OUTDIR)/.phony
-	@$(CC) -o $(OUT) $(OFILES) $(xLDFLAGS)
-	@echo ====== Linked $(OUT)
-
-.SECONDEXPANSION:
-$(OBJDIR)/%.o: %.c $(xHFILES) | $$(dir $$@).phony
-	@$(CC) -o $@ -c $< $(xCFLAGS)
-	@echo ====== Compiled $<
-
-$(OBJDIR)/%.o: %.m $(xHFILES) | $$(dir $$@).phony
-	@$(CC) -o $@ -c $< $(xCFLAGS)
-	@echo ====== Compiled $<
-
-$(OBJDIR)/%.o: %.rc $(xHFILES) | $$(dir $$@).phony
-	@$(RC) $(xRCFLAGS) $< $@
-	@echo ====== Compiled $<
-
-# see http://www.cmcrossroads.com/article/making-directories-gnu-make
-%/.phony:
-	@mkdir -p $(dir $@)
-	@touch $@
-.PRECIOUS: %/.phony
-
-clean:
-	rm -rf $(OUTDIR) $(OBJDIR) z*
-.PHONY: clean
diff --git a/GNUbaserules.mk b/GNUbaserules.mk
new file mode 100644
index 00000000..fa8e90fd
--- /dev/null
+++ b/GNUbaserules.mk
@@ -0,0 +1,56 @@
+# 16 october 2015
+
+OUTDIR = out
+OBJDIR = .obj
+
+OFILES = \
+	$(subst /,_,$(CFILES)) \
+	$(subst /,_,$(MFILES)) \
+	$(subst /,_,$(RCFILES))
+
+OFILES := $(OFILES:%=$(OBJDIR)/%.o)
+
+CFLAGS += \
+	-g \
+	-Wall -Wextra \
+	-Wno-unused-parameter \
+	-Wno-switch \
+	--std=c99
+
+LDFLAGS += \
+	-g
+
+ifeq ($(ARCH),386)
+	CFLAGS += -m32
+	LDFLAGS += -m32
+else ifeq ($(ARCH),amd64)
+	CFLAGS += -m64
+	LDFLAGS += -m64
+endif
+
+OUT = $(OUTDIR)/$(NAME)$(SUFFIX)
+
+$(OUT): $(OFILES) | $(OUTDIR)
+	@$(CC) -o $(OUT) $(OFILES) $(LDFLAGS)
+	@echo ====== Linked $(OUT)
+
+.SECONDEXPANSION:
+
+$(OBJDIR)/%.c.o: $$(subst _,/,%).c $(HFILES) | $(OBJDIR)
+	@$(CC) -o $@ -c $< $(CFLAGS)
+	@echo ====== Compiled $<
+
+$(OBJDIR)/%.m.o: $$(subst _,/,%).m $(HFILES) | $(OBJDIR)
+	@$(CC) -o $@ -c $< $(CFLAGS)
+	@echo ====== Compiled $<
+
+$(OBJDIR)/%.rc.o: $$(subst _,/,%).rc $(HFILES) | $(OBJDIR)
+	@$(RC) $(RCFLAGS) $< $@
+	@echo ====== Compiled $<
+
+$(OBJDIR) $(OUTDIR):
+	@mkdir -p $@
+
+clean:
+	rm -rf $(OBJDIR) $(OUTDIR)
+.PHONY: clean
diff --git a/GNUmakefile b/GNUmakefile
index 7de974ad..f15f7450 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -1,51 +1,38 @@
-# 22 april 2015
+# 16 october 2015
+
+# silence entering/leaving messages
+MAKEFLAGS += --no-print-directory
 
 # MAME does this so :/
 ifeq ($(OS),Windows_NT)
-OS = windows
+	OS = windows
 endif
 
 ifndef OS
-UNAME = $(shell uname -s)
-ifeq ($(UNAME),Darwin)
-OS = darwin
-else
-OS = unix
-endif
+	UNAME = $(shell uname -s)
+	ifeq ($(UNAME),Darwin)
+		OS = darwin
+	else
+		OS = unix
+	endif
 endif
 
-include $(OS)/GNUmakeinc.mk
+ifndef ARCH
+	UNAME = $(shell uname -m)
+	ifeq ($(UNAME),x86_64)
+		ARCH = amd64
+	else ifeq ($(UNAME),i686)
+		ARCH = 386
+	else
+		ARCH = default
+	endif
+endif
 
-baseHFILES = \
-	ui.h \
-	uipriv.h \
-	ui_$(OS).h \
-	$(osHFILES)
+libui:
+	@$(MAKE) -f GNUmakefile.libui OS=$(OS) ARCH=$(ARCH)
 
-baseCFILES = \
-	areaevents.c \
-	control.c \
-	matrix.c \
-	menu.c \
-	ptrarray.c \
-	shouldquit.c \
-	types.c \
-	$(osCFILES)
+clean:
+	@$(MAKE) -f GNUmakefile.libui OS=$(OS) ARCH=$(ARCH) clean
 
-baseMFILES = $(osMFILES)
-
-baseRCFILES = $(osRCFILES)
-
-baseCFLAGS = $(osCFLAGS)
-baseLDFLAGS = \
-	-shared \
-	$(osLDWarnUndefinedFlags) \
-	$(osLDFLAGS)
-baseRCFLAGS = $(osRCFLAGS)
-baseSUFFIX = $(osLIBSUFFIX)
-
-include GNUbase.mk
-
-test: $(OUT)
-	@$(MAKE) -f GNUmaketest.mk osLIB=$(OUT) osEXESUFFIX=$(osEXESUFFIX) CC=$(CC) archmflag=$(archmflag)
-.PHONY: test
+test: libui
+	@$(MAKE) -f GNUmakefile.test OS=$(OS) ARCH=$(ARCH)
diff --git a/GNUmakefile.libui b/GNUmakefile.libui
new file mode 100644
index 00000000..3fe03647
--- /dev/null
+++ b/GNUmakefile.libui
@@ -0,0 +1,16 @@
+# 16 october 2015
+
+include common/GNUmakeinc.mk
+include $(OS)/GNUmakeinc.mk
+
+HFILES += \
+	ui.h \
+	ui_$(OS).h
+
+NAME = libui
+
+LDFLAGS += \
+	-shared \
+	-Wl,-soname,$(NAME)$(SUFFIX).0
+
+include GNUbaserules.mk
diff --git a/GNUmakefile.test b/GNUmakefile.test
new file mode 100644
index 00000000..ae9d1c65
--- /dev/null
+++ b/GNUmakefile.test
@@ -0,0 +1,41 @@
+# 16 october 2015
+
+include test/GNUmakeinc.mk
+
+HFILES += \
+	ui.h
+
+NAME = test
+
+SUFFIX =
+ifeq ($(OS),windows)
+	SUFFIX = .exe
+endif
+
+# TODO split out this logic somehow
+ifeq ($(OS),windows)
+ifeq ($(ARCH),amd64)
+	ifndef CC
+		CC = x86_64-w64-mingw32-gcc
+	endif
+	ifndef RC
+		RC = x86_64-w64-mingw32-windres
+	endif
+else ifeq ($(ARCH),386)
+	ifndef CC
+		CC = i686-w64-mingw32-gcc
+	endif
+	ifndef RC
+		RC = i686-w64-mingw32-windres
+	endif
+else ifneq ($(ARCH),default)
+	$(error [FAIL] unknown architecture $(ARCH))
+endif
+	LDFLAGS += out/libui.dll
+else ifeq ($(OS),darwin)
+	LDFLAGS += out/libui.dylib
+else
+	LDFLAGS += out/libui.so
+endif
+
+include GNUbaserules.mk
diff --git a/GNUmaketest.mk b/GNUmaketest.mk
deleted file mode 100644
index 25194a9d..00000000
--- a/GNUmaketest.mk
+++ /dev/null
@@ -1,15 +0,0 @@
-# 22 april 2015
-# should never be invoked directly, only ever from the main makefile
-
-include test/GNUmakeinc.mk
-
-baseHFILES = \
-	$(testHFILES)
-
-baseCFILES = $(testCFILES)
-
-baseCFLAGS = $(testCFLAGS)
-baseLDFLAGS = $(osLIB) $(testLDFLAGS)
-baseSUFFIX = $(osEXESUFFIX)
-
-include GNUbase.mk
diff --git a/common/GNUmakeinc.mk b/common/GNUmakeinc.mk
new file mode 100644
index 00000000..e7fb9522
--- /dev/null
+++ b/common/GNUmakeinc.mk
@@ -0,0 +1,13 @@
+# 16 october 2015
+
+CFILES += \
+	common/areaevents.c \
+	common/control.c \
+	common/matrix.c \
+	common/menu.c \
+	common/ptrarray.c \
+	common/shouldquit.c \
+	common/types.c
+
+HFILES += \
+	common/uipriv.h
diff --git a/darwin/GNUmakeinc.mk b/darwin/GNUmakeinc.mk
index 3f0d2a20..b6c90e6b 100644
--- a/darwin/GNUmakeinc.mk
+++ b/darwin/GNUmakeinc.mk
@@ -1,6 +1,6 @@
 # 28 april 2015
 
-osMFILES = \
+MFILES += \
 	darwin/alloc.m \
 	darwin/area.m \
 	darwin/areaevents.m \
@@ -29,26 +29,24 @@ osMFILES = \
 	darwin/util.m \
 	darwin/window.m
 
-osHFILES = \
+HFILES += \
 	darwin/uipriv_darwin.h
 
-osCFLAGS = \
+CFLAGS += \
 	-D_UI_EXTERN='__attribute__((visibility("default"))) extern' \
 	-fvisibility=hidden \
-	-mmacosx-version-min=10.7 -DMACOSX_DEPLOYMENT_TARGET=10.7
-osLDFLAGS = \
-	-fvisibility=hidden \
-	-mmacosx-version-min=10.7 -lobjc -framework Foundation -framework AppKit
+	-mmacosx-version-min=10.7 \
+	-DMACOSX_DEPLOYMENT_TARGET=10.7
 
+LDFLAGS += \
+	-fvisibility=hidden \
+	-mmacosx-version-min=10.7 \
+	-lobjc \
+	-framework Foundation \
+	-framework AppKit
+
+# on warning about undefined symbols:
 # the gcc flags don't work with Apple's linker
 # fortunately, we don't need any; Apple's linker warns about undefined symbols in -shared builds!
-osLDWarnUndefinedFlags = 
 
-osLIBSUFFIX = .dylib
-osEXESUFFIX =
-
-ifeq ($(ARCH),386)
-	archmflag = -m32
-else
-	archmflag = -m64
-endif
+SUFFIX = .dylib
diff --git a/test/GNUmakeinc.mk b/test/GNUmakeinc.mk
index e2b5ead8..1868dac8 100644
--- a/test/GNUmakeinc.mk
+++ b/test/GNUmakeinc.mk
@@ -1,6 +1,6 @@
 # 22 april 2015
 
-testCFILES = \
+CFILES += \
 	test/drawtests.c \
 	test/main.c \
 	test/menus.c \
@@ -13,5 +13,5 @@ testCFILES = \
 	test/page7.c \
 	test/spaced.c
 
-testHFILES = \
+HFILES += \
 	test/test.h
diff --git a/unix/GNUmakeinc.mk b/unix/GNUmakeinc.mk
index 1307550a..bc920610 100644
--- a/unix/GNUmakeinc.mk
+++ b/unix/GNUmakeinc.mk
@@ -1,6 +1,6 @@
 # 22 april 2015
 
-osCFILES = \
+CFILES += \
 	unix/alloc.c \
 	unix/area.c \
 	unix/box.c \
@@ -27,22 +27,23 @@ osCFILES = \
 	unix/util.c \
 	unix/window.c
 
-osHFILES = \
+HFILES += \
 	unix/uipriv_unix.h
 
 # thanks ebassi in irc.gimp.net/#gtk+
-osCFLAGS = \
+CFLAGS += \
 	-D_UI_EXTERN='__attribute__((visibility("default"))) extern' \
 	-fvisibility=hidden \
 	-fPIC \
 	`pkg-config --cflags gtk+-3.0`
 
-osLDFLAGS = \
+LDFLAGS += \
 	-fvisibility=hidden \
 	-fPIC \
 	`pkg-config --libs gtk+-3.0` -lm
 
-osLDWarnUndefinedFlags = -Wl,--no-undefined -Wl,--no-allow-shlib-undefined
+# flags for warning on undefined symbols
+LDFLAGS += \
+	-Wl,--no-undefined -Wl,--no-allow-shlib-undefined
 
-osLIBSUFFIX = .so
-osEXESUFFIX =
+SUFFIX = .so
diff --git a/windows/GNUmakeinc.mk b/windows/GNUmakeinc.mk
index ffc096c1..f2aa682e 100644
--- a/windows/GNUmakeinc.mk
+++ b/windows/GNUmakeinc.mk
@@ -1,6 +1,6 @@
 # 22 april 2015
 
-osCFILES = \
+CFILES += \
 	windows/alloc.c \
 	windows/area.c \
 	windows/box.c \
@@ -36,34 +36,43 @@ osCFILES = \
 	windows/utilwin.c \
 	windows/window.c
 
-osHFILES = \
+HFILES += \
 	windows/compilerver.h \
 	windows/resources.h \
 	windows/uipriv_windows.h \
 	windows/winapi.h
 
-osRCFILES = \
+RCFILES += \
 	windows/resources.rc
 
 # thanks ebassi in irc.gimp.net/#gtk+
-osCFLAGS = \
+CFLAGS += \
 	-D_UI_EXTERN='__declspec(dllexport) extern'
 
-osLDFLAGS = \
+LDFLAGS += \
 	-static-libgcc \
 	-luser32 -lkernel32 -lgdi32 -lcomctl32 -luxtheme -lmsimg32 -lcomdlg32 -ld2d1 -lole32 -loleaut32 -loleacc -luuid
 
-osLDWarnUndefinedFlags = -Wl,--no-undefined -Wl,--no-allow-shlib-undefined
+# warnings on undefined symbols
+LDFLAGS += \
+	-Wl,--no-undefined -Wl,--no-allow-shlib-undefined
 
-osLIBSUFFIX = .dll
-osEXESUFFIX = .exe
+SUFFIX = .dll
 
 ifeq ($(ARCH),amd64)
-	CC = x86_64-w64-mingw32-gcc
-	RC = x86_64-w64-mingw32-windres
-	archmflag = -m64
-else
-	CC = i686-w64-mingw32-gcc
-	RC = i686-w64-mingw32-windres
-	archmflag = -m32
+	ifndef CC
+		CC = x86_64-w64-mingw32-gcc
+	endif
+	ifndef RC
+		RC = x86_64-w64-mingw32-windres
+	endif
+else ifeq ($(ARCH),386)
+	ifndef CC
+		CC = i686-w64-mingw32-gcc
+	endif
+	ifndef RC
+		RC = i686-w64-mingw32-windres
+	endif
+else ifneq ($(ARCH),default)
+	$(error [FAIL] unknown architecture $(ARCH))
 endif