diff --git a/Tuprules.tup b/Tuprules.tup
index c2bed0982..3531f0578 100644
--- a/Tuprules.tup
+++ b/Tuprules.tup
@@ -71,7 +71,8 @@ export PKG_CONFIG_PATH
 PKG_CONFIG_DIR = $(DEV_DIR)/lib/pkgconfig
 PKG_CONFIG = PKG_CONFIG_PATH=$(PKG_CONFIG_DIR):$PKG_CONFIG_PATH pkg-config
 
-DEFINES += -g
+CFLAGS += -g
+CXXFLAGS += -g
 
 ifdef OLEVEL
 OLEVEL = @(OLEVEL)
@@ -79,13 +80,13 @@ else
 OLEVEL = -O0
 endif
 
-!ir = | $(GENODE_DIR)/<pkg-config> |> clang $(OLEVEL) $(DEFINES) $(CXXFLAGS) $(CXXFLAGS_%e) $(CXXFLAGS_%f) `$(PKG_CONFIG) --cflags $(LIBS)` $(INCLUDES) -S -emit-llvm %f |> %B.ll
+!ir = | $(GENODE_DIR)/<pkg-config> |> clang $(OLEVEL) $(CXXFLAGS) $(CXXFLAGS_%e) $(CXXFLAGS_%f) `$(PKG_CONFIG) --cflags $(LIBS)` $(CPPFLAGS) -S -emit-llvm %f |> %B.ll
 
-!asm = |> ^ CC %b^ @(CC_WRAPPER) $(CC) $(OLEVEL) $(DEFINES) $(CFLAGS) $(CFLAGS_%e) $(CFLAGS_%f) -D__ASSEMBLY__ $(INCLUDES) -c %f -o %o |> %B.o
+!asm = |> ^ CC %b^ @(CC_WRAPPER) $(CC) $(OLEVEL) $(CFLAGS) $(CFLAGS_%e) $(CFLAGS_%f) -D__ASSEMBLY__ $(CPPFLAGS) -c %f -o %o |> %B.o
 
-!cc = | $(GENODE_DIR)/<pkg-config> |> ^o CC %f^ @(CC_WRAPPER) $(CC) $(OLEVEL) $(DEFINES) $(CFLAGS) $(CFLAGS_%e) $(CFLAGS_%f) $(INCLUDES) `$(PKG_CONFIG) --cflags $(LIBS) $(LIBS_CFLAGS)` -c -fPIC %f -o %o |> %B.o
+!cc = | $(GENODE_DIR)/<pkg-config> |> ^o CC %f^ @(CC_WRAPPER) $(CC) $(OLEVEL) $(CFLAGS) $(CFLAGS_%e) $(CFLAGS_%f) $(CPPFLAGS) `$(PKG_CONFIG) --cflags $(LIBS) $(LIBS_CFLAGS)` -c -fPIC %f -o %o |> %B.o
 
-!cxx = | $(GENODE_DIR)/<pkg-config> |> ^o CXX %b^ @(CC_WRAPPER) $(CXX) $(OLEVEL) $(DEFINES) $(CXXFLAGS) $(CXXFLAGS_%e) $(CXXFLAGS_%f) $(INCLUDES) `$(PKG_CONFIG) --cflags $(LIBS)` -c -fPIC %f -o %o |> %B.o
+!cxx = | $(GENODE_DIR)/<pkg-config> |> ^o CXX %b^ @(CC_WRAPPER) $(CXX) $(OLEVEL) $(CXXFLAGS) $(CXXFLAGS_%e) $(CXXFLAGS_%f) $(CPPFLAGS) `$(PKG_CONFIG) --cflags $(LIBS)` -c -fPIC %f -o %o |> %B.o
 
 !ld = | $(GENODE_DIR)/<lib> $(GENODE_DIR)/<pkg-config> |> ^o LD %o^ $(LD) $(LDFLAGS) `$(PKG_CONFIG) --libs $(LIBS)` --whole-archive --start-group %f --no-whole-archive --end-group -o %o |>
 
diff --git a/repos/base-linux/src/Tuprules.tup b/repos/base-linux/src/Tuprules.tup
index 24ff01a2a..1f2ea88c8 100644
--- a/repos/base-linux/src/Tuprules.tup
+++ b/repos/base-linux/src/Tuprules.tup
@@ -2,6 +2,6 @@ ifndef LINUX_HEADERS
 error CONFIG_LINUX_HEADERS not defined
 endif
 
-INCLUDES += -I$(TUP_CWD)/include
-INCLUDES += -I$(BASE_DIR)/src/include
-INCLUDES += -I@(LINUX_HEADERS)/include
+CPPFLAGS += -I$(TUP_CWD)/include
+CPPFLAGS += -I$(BASE_DIR)/src/include
+CPPFLAGS += -I@(LINUX_HEADERS)/include
diff --git a/repos/base-linux/src/core/Tupfile b/repos/base-linux/src/core/Tupfile
index 1d4ca3f2c..8d7a1959a 100644
--- a/repos/base-linux/src/core/Tupfile
+++ b/repos/base-linux/src/core/Tupfile
@@ -2,9 +2,9 @@
 include_rules
 GEN_CORE_DIR = $(BASE_DIR)/src/core
 
-DEFINES += -D_GNU_SOURCE
+CPPFLAGS += -D_GNU_SOURCE
 
-INCLUDES += \
+CPPFLAGS += \
 	-I$(REP_DIR)/src/core/include \
 	-I$(GEN_CORE_DIR)/include \
 
diff --git a/repos/base-linux/src/lib/base/Tupfile b/repos/base-linux/src/lib/base/Tupfile
index 42f1cba39..103ad5477 100644
--- a/repos/base-linux/src/lib/base/Tupfile
+++ b/repos/base-linux/src/lib/base/Tupfile
@@ -1,6 +1,6 @@
 include_rules
 
-INCLUDES += -I$(REP_DIR)/src/lib/syscall
+CPPFLAGS += -I$(REP_DIR)/src/lib/syscall
 
 BASE_LIB_DIR = $(BASE_DIR)/src/lib/base
 
diff --git a/repos/base-linux/src/lib/ld/Tupfile b/repos/base-linux/src/lib/ld/Tupfile
index a43b3d4ec..340f77a81 100644
--- a/repos/base-linux/src/lib/ld/Tupfile
+++ b/repos/base-linux/src/lib/ld/Tupfile
@@ -1,7 +1,7 @@
 include_rules
 
 ifeq (@(TUP_ARCH),x86_64)
-	INCLUDES += -I$(BASE_DIR)/src/lib/ldso/spec/x86_64
+	CPPFLAGS += -I$(BASE_DIR)/src/lib/ldso/spec/x86_64
 endif
 
 LDSO_DIR = $(BASE_DIR)/src/lib/ldso
@@ -10,10 +10,8 @@ ifeq (@(TUP_ARCH),x86_64)
 LDSO_SPEC_DIR = $(LDSO_DIR)/spec/x86_64
 endif
 
-INCLUDES += -I$(LDSO_SPEC_DIR)
-INCLUDES = -I$(LDSO_DIR)/include $(INCLUDES)
-
-DEFINES += -fPIC
+CPPFLAGS += -I$(LDSO_SPEC_DIR)
+CPPFLAGS = -I$(LDSO_DIR)/include $(CPPFLAGS)
 
 : foreach $(LDSO_DIR)/*.cc |> !cxx |> {obj}
 : foreach $(LDSO_SPEC_DIR)/*.s |> !asm |> {obj}
diff --git a/repos/base-linux/src/lib/lx_hybrid/Tupfile b/repos/base-linux/src/lib/lx_hybrid/Tupfile
index f8376acf1..f833fb3f9 100644
--- a/repos/base-linux/src/lib/lx_hybrid/Tupfile
+++ b/repos/base-linux/src/lib/lx_hybrid/Tupfile
@@ -1,6 +1,6 @@
 include_rules
 
-INCLUDES += -I$(REP_DIR)/src/lib/syscall
+CPPFLAGS += -I$(REP_DIR)/src/lib/syscall
 
 : foreach *.cc $(BASE_DIR)/src/lib/cxx/new_delete.cc |> !cxx |> {obj}
 : foreach *.c |> !cc |> {obj}
diff --git a/repos/base-linux/src/timer/linux/Tupfile b/repos/base-linux/src/timer/linux/Tupfile
index 499742197..a8608bb81 100644
--- a/repos/base-linux/src/timer/linux/Tupfile
+++ b/repos/base-linux/src/timer/linux/Tupfile
@@ -5,11 +5,11 @@ BASE_TIMER_DIR = $(BASE_DIR)/src/timer
 
 PERIODIC_DIR = $(BASE_TIMER_DIR)/periodic
 
-INCLUDES += -I$(BASE_TIMER_DIR)/include
-INCLUDES += -I$(PERIODIC_DIR)
-INCLUDES += -I$(REP_DIR)/src/lib/syscall
+CPPFLAGS += -I$(BASE_TIMER_DIR)/include
+CPPFLAGS += -I$(PERIODIC_DIR)
+CPPFLAGS += -I$(REP_DIR)/src/lib/syscall
 
-INCLUDES = -I. $(INCLUDES)
+CPPFLAGS = -I. $(CPPFLAGS)
 	#TODO: ^ FAIL
 
 : foreach $(BASE_TIMER_DIR)/*.cc |> !cxx |> %B.linux.o {obj}
diff --git a/repos/base-nova/Tuprules.tup b/repos/base-nova/Tuprules.tup
index 7f19d025f..7728c4dd1 100644
--- a/repos/base-nova/Tuprules.tup
+++ b/repos/base-nova/Tuprules.tup
@@ -1,12 +1,12 @@
 ifeq (@(TUP_ARCH),x86_32)
-	INCLUDES += -I$(TUP_CWD)/include/spec/64bit
+	CPPFLAGS += -I$(TUP_CWD)/include/spec/64bit
 endif
 
 ifeq (@(TUP_ARCH),x86_64)
-	INCLUDES += -I$(TUP_CWD)/include/spec/64bit
+	CPPFLAGS += -I$(TUP_CWD)/include/spec/64bit
 endif
 
-INCLUDES += -I$(TUP_CWD)/include
+CPPFLAGS += -I$(TUP_CWD)/include
 
 include &(BASE_DIR)/Tuprules.tup
 REP_DIR = $(TUP_CWD)
diff --git a/repos/base-nova/src/Tuprules.tup b/repos/base-nova/src/Tuprules.tup
index b3cb0d6c0..fc6f26223 100644
--- a/repos/base-nova/src/Tuprules.tup
+++ b/repos/base-nova/src/Tuprules.tup
@@ -1 +1 @@
-INCLUDES = -I$(TUP_CWD)/include -I$(BASE_DIR)/src/include $(INCLUDES)
+CPPFLAGS = -I$(TUP_CWD)/include -I$(BASE_DIR)/src/include $(CPPFLAGS)
diff --git a/repos/base-nova/src/core/Tupfile b/repos/base-nova/src/core/Tupfile
index c6902a784..9ff9c68ce 100644
--- a/repos/base-nova/src/core/Tupfile
+++ b/repos/base-nova/src/core/Tupfile
@@ -1,7 +1,7 @@
 include_rules
 GEN_CORE_DIR = $(BASE_DIR)/src/core
 
-INCLUDES += \
+CPPFLAGS += \
 	-I$(TUP_CWD)/include \
 	-I$(GEN_CORE_DIR)/include \
 
diff --git a/repos/base-nova/src/lib/ld/Tupfile b/repos/base-nova/src/lib/ld/Tupfile
index f2b5db802..ec7eb7826 100644
--- a/repos/base-nova/src/lib/ld/Tupfile
+++ b/repos/base-nova/src/lib/ld/Tupfile
@@ -1,5 +1,5 @@
 include_rules
-INCLUDES += -I$(BASE_DIR)/src/include
+CPPFLAGS += -I$(BASE_DIR)/src/include
 
 LDSO_DIR = $(BASE_DIR)/src/lib/ldso
 
@@ -7,10 +7,8 @@ ifeq (@(TUP_ARCH),x86_64)
 LDSO_SPEC_DIR = $(LDSO_DIR)/spec/x86_64
 endif
 
-INCLUDES += -I$(LDSO_SPEC_DIR)
-INCLUDES += -I$(LDSO_DIR)/include
-
-DEFINES += -fPIC
+CPPFLAGS += -I$(LDSO_SPEC_DIR)
+CPPFLAGS += -I$(LDSO_DIR)/include
 
 : foreach $(LDSO_DIR)/*.cc |> !cxx |> {obj}
 : foreach $(LDSO_SPEC_DIR)/*.s |> !asm |> {obj}
diff --git a/repos/base-nova/src/timer/nova/Tupfile b/repos/base-nova/src/timer/nova/Tupfile
index ae61efbd3..a99741494 100644
--- a/repos/base-nova/src/timer/nova/Tupfile
+++ b/repos/base-nova/src/timer/nova/Tupfile
@@ -3,8 +3,8 @@ include_rules
 
 BASE_TIMER_DIR = $(BASE_DIR)/src/timer
 
-INCLUDES += -I$(BASE_TIMER_DIR)/include
-INCLUDES += -I.
+CPPFLAGS += -I$(BASE_TIMER_DIR)/include
+CPPFLAGS += -I.
 	#TODO: ^ FAIL
 
 : foreach *.cc $(BASE_TIMER_DIR)/*.cc |> !cxx |> %B.nova.o {obj}
diff --git a/repos/base/Tuprules.tup b/repos/base/Tuprules.tup
index 59780bbec..6a8525703 100644
--- a/repos/base/Tuprules.tup
+++ b/repos/base/Tuprules.tup
@@ -1,50 +1,46 @@
 REP_DIR = $(TUP_CWD)
 
 ifeq (@(TUP_ARCH),i386)
-INCLUDES += -I$(BASE_DIR)/include/spec/x86_32
-INCLUDES += -I$(BASE_DIR)/include/spec/x86
-INCLUDES += -I$(BASE_DIR)/include/spec/32bit
+CPPFLAGS += -I$(BASE_DIR)/include/spec/x86_32
+CPPFLAGS += -I$(BASE_DIR)/include/spec/x86
+CPPFLAGS += -I$(BASE_DIR)/include/spec/32bit
 endif
 
 ifeq (@(TUP_ARCH),x86_64)
-INCLUDES += -I$(BASE_DIR)/include/spec/x86_64
-INCLUDES += -I$(BASE_DIR)/include/spec/x86
-INCLUDES += -I$(BASE_DIR)/include/spec/64bit
+CPPFLAGS += -I$(BASE_DIR)/include/spec/x86_64
+CPPFLAGS += -I$(BASE_DIR)/include/spec/x86
+CPPFLAGS += -I$(BASE_DIR)/include/spec/64bit
 endif
 
 ifeq (@(TUP_ARCH),arm64)
-INCLUDES += -I$(BASE_DIR)/include/spec/arm_64
-INCLUDES += -I$(BASE_DIR)/include/spec/64bit
+CPPFLAGS += -I$(BASE_DIR)/include/spec/arm_64
+CPPFLAGS += -I$(BASE_DIR)/include/spec/64bit
 endif
 
-INCLUDES += -I$(BASE_DIR)/include
+CPPFLAGS += -I$(BASE_DIR)/include
 
 # Override base macros to bypass pkg-config
 
-DEFINES += \
+CXXFLAGS += \
 	-ffunction-sections \
 	-fno-strict-aliasing \
-	-fPIC \
-	-g \
 	-nostdinc \
 	-Wall \
-
-CXXFLAGS += \
 	-std=gnu++17 \
 
 GCC_INCLUDE = -I`$(CC) -print-file-name=include`
 
 !cc = |> ^ COMPILE %b^ \
-	@(CC_WRAPPER) $(CC) $(DEFINES) $(OLEVEL) \
+	@(CC_WRAPPER) $(CC) $(OLEVEL) -fPIC \
 	$(CFLAGS) $(CFLAGS_%e) $(CFLAGS_%f) \
-	$(INCLUDES) $(GCC_INCLUDE) $(CC_MARCH) \
+	$(CPPFLAGS) $(GCC_INCLUDE) $(CC_MARCH) \
 	-c %f -o %o \
 |> %B.o
 
 !cxx = |> ^ COMPILE %b^ \
-	@(CC_WRAPPER) $(CXX) $(DEFINES) $(OLEVEL) \
+	@(CC_WRAPPER) $(CXX) $(OLEVEL) -fPIC \
 	$(CXXFLAGS) $(CXXFLAGS_%e) $(CXXFLAGS_%f) \
-	$(INCLUDES) $(GCC_INCLUDE) $(CC_MARCH) \
+	$(CPPFLAGS) $(GCC_INCLUDE) $(CC_MARCH) \
 	-c %f -o %o \
 |> %B.o
 
diff --git a/repos/base/src/Tuprules.tup b/repos/base/src/Tuprules.tup
index 099a50f28..9affdecbd 100644
--- a/repos/base/src/Tuprules.tup
+++ b/repos/base/src/Tuprules.tup
@@ -1 +1 @@
-INCLUDES += -I$(REP_DIR)/src/include
+CPPFLAGS += -I$(REP_DIR)/src/include
diff --git a/repos/base/src/lib/cxx/Tupfile b/repos/base/src/lib/cxx/Tupfile
index 5e8d346ca..a339eb0e9 100644
--- a/repos/base/src/lib/cxx/Tupfile
+++ b/repos/base/src/lib/cxx/Tupfile
@@ -16,11 +16,13 @@ endif
 
 include_rules
 
-DEFINES = -ffunction-sections -fno-strict-aliasing -g -fPIC
-	# drop the standard defines to avoid -nostdinc
+COMMON_FLAGS = -ffunction-sections -fno-strict-aliasing
 
-INCLUDES += -I@(LIBCXX)/include/c++/v1
-INCLUDES += -I@(LIBCXXABI)/include
+CFLAGS += $(COMMON_FLAGS)
+CXXFLAGS += $(COMMON_FLAGS)
+
+CPPFLAGS += -I@(LIBCXX)/include/c++/v1
+CPPFLAGS += -I@(LIBCXXABI)/include
 
 LLVM_LIBS += @(LIBCXXABI)/lib/libc++abi.a
 
diff --git a/repos/base/src/lib/timeout/Tupfile b/repos/base/src/lib/timeout/Tupfile
index f858c9acc..3992c4b7c 100644
--- a/repos/base/src/lib/timeout/Tupfile
+++ b/repos/base/src/lib/timeout/Tupfile
@@ -1,5 +1,5 @@
 include_rules
-INCLUDES += $(REP_DIR)/src/include
+CPPFLAGS += $(REP_DIR)/src/include
 
 SRC_CC += \
 	duration.cc \
diff --git a/repos/os/Tuprules.tup b/repos/os/Tuprules.tup
index 4c68f22dc..1cffbd369 100644
--- a/repos/os/Tuprules.tup
+++ b/repos/os/Tuprules.tup
@@ -1,19 +1,19 @@
 REP_DIR = $(TUP_CWD)
 
 ifeq (@(TUP_ARCH),i386)
-INCLUDES += -I$(REP_DIR)/include/spec/x86_32
-INCLUDES += -I$(REP_DIR)/include/spec/x86
+CPPFLAGS += -I$(REP_DIR)/include/spec/x86_32
+CPPFLAGS += -I$(REP_DIR)/include/spec/x86
 endif
 
 ifeq (@(TUP_ARCH),x86_64)
-INCLUDES += -I$(REP_DIR)/include/spec/x86_64
-INCLUDES += -I$(REP_DIR)/include/spec/x86
+CPPFLAGS += -I$(REP_DIR)/include/spec/x86_64
+CPPFLAGS += -I$(REP_DIR)/include/spec/x86
 endif
 
 ifeq (@(TUP_ARCH),arm)
-INCLUDES += -I$(REP_DIR)/include/spec/arm
+CPPFLAGS += -I$(REP_DIR)/include/spec/arm
 endif
 
-INCLUDES += -I$(REP_DIR)/include
+CPPFLAGS += -I$(REP_DIR)/include
 
 CXXFLAGS += -std=gnu++17
diff --git a/repos/os/src/drivers/ahci/Tuprules.tup b/repos/os/src/drivers/ahci/Tuprules.tup
index 22e944acd..5bf8d761f 100644
--- a/repos/os/src/drivers/ahci/Tuprules.tup
+++ b/repos/os/src/drivers/ahci/Tuprules.tup
@@ -1,2 +1,2 @@
-INCLUDES += -I$(TUP_CWD)
+CPPFLAGS += -I$(TUP_CWD)
 SRC_CC = $(TUP_CWD)/*.cc
diff --git a/repos/os/src/drivers/input/spec/ps2/Tuprules.tup b/repos/os/src/drivers/input/spec/ps2/Tuprules.tup
index 8e021bbf4..7d2300e14 100644
--- a/repos/os/src/drivers/input/spec/ps2/Tuprules.tup
+++ b/repos/os/src/drivers/input/spec/ps2/Tuprules.tup
@@ -1 +1 @@
-INCLUDES += -I$(TUP_CWD)
+CPPFLAGS += -I$(TUP_CWD)
diff --git a/repos/os/src/lib/blit/Tupfile b/repos/os/src/lib/blit/Tupfile
index 7286c3867..c4dd19c22 100644
--- a/repos/os/src/lib/blit/Tupfile
+++ b/repos/os/src/lib/blit/Tupfile
@@ -1,24 +1,24 @@
 include_rules
 
 ifeq (@(TUP_ARCH),i386)
-BLIT_INCLUDES += -Ispec/x86_32
-BLIT_INCLUDES += -Ispec/x86
+BLIT_CPPFLAGS += -Ispec/x86_32
+BLIT_CPPFLAGS += -Ispec/x86
 endif
 
 ifeq (@(TUP_ARCH),x86_64)
-BLIT_INCLUDES += -Ispec/x86_64
-BLIT_INCLUDES += -Ispec/x86
+BLIT_CPPFLAGS += -Ispec/x86_64
+BLIT_CPPFLAGS += -Ispec/x86
 endif
 
 ifeq (@(TUP_ARCH),arm)
-BLIT_INCLUDES += -Ispec/arm
+BLIT_CPPFLAGS += -Ispec/arm
 endif
 
-ifeq ($(BLIT_INCLUDES),)
+ifeq ($(BLIT_CPPFLAGS),)
 error blit library not yet ported to @(TUP_ARCH)
 endif
 
-INCLUDES += $(BLIT_INCLUDES)
+CPPFLAGS += $(BLIT_CPPFLAGS)
 
 : foreach *.cc |> !cxx |> {obj}
 : {obj} |> !ar |> {bin}