diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..d21b4c2
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,54 @@
+.PHONY = agbcc old_agbcc agbcc_arm libc.a libgcc.a
+
+# needed for out-of-tree builds of agbcc and old_agbcc
+export srcdir = ../gcc
+
+all: agbcc old_agbcc agbcc_arm libc.a libgcc.a
+
+clean:
+	rm -rf build_agbcc build_old_agbcc
+	-$(MAKE) -C gcc_arm distclean
+	$(MAKE) -C libc clean
+	$(MAKE) -C libgcc clean
+
+agbcc:
+	mkdir -p build_agbcc
+	$(MAKE) -C build_agbcc -f ../gcc/Makefile clean
+	$(MAKE) -C build_agbcc -f ../gcc/Makefile normal
+
+old_agbcc:
+	mkdir -p build_old_agbcc
+	$(MAKE) -C build_old_agbcc -f ../gcc/Makefile clean
+	$(MAKE) -C build_old_agbcc -f ../gcc/Makefile old
+
+agbcc_arm:
+	-$(MAKE) -C gcc_arm distclean
+	cd gcc_arm && ./configure --target=arm-elf --host=i386-linux-gnu
+	$(MAKE) -C gcc_arm cc1
+
+libc.a: old_agbcc
+	$(MAKE) -C libc clean
+	$(MAKE) -C libc
+
+libgcc.a: old_agbcc
+	$(MAKE) -C libgcc clean
+	$(MAKE) -C libgcc
+
+install: all
+ifeq ($(PREFIX),)
+	$(error PREFIX is empty! Specify a PREFIX to install to)
+endif
+	$(info Installing into $(PREFIX))
+	mkdir -p $(PREFIX)/tools/agbcc
+	mkdir -p $(PREFIX)/tools/agbcc/bin
+	mkdir -p $(PREFIX)/tools/agbcc/include
+	mkdir -p $(PREFIX)/tools/agbcc/lib
+	cp build_agbcc/agbcc $(PREFIX)/tools/agbcc/bin/
+	cp build_old_agbcc/old_agbcc $(PREFIX)/tools/agbcc/bin/
+	cp gcc_arm/cc1 $(PREFIX)/tools/agbcc/bin/agbcc_arm
+	@# drop include, because we don't want include/include
+	cp -R libc/include $(PREFIX)/tools/agbcc/
+	cp ginclude/* $(PREFIX)/tools/agbcc/include/
+	cp libgcc/libgcc.a $(PREFIX)/tools/agbcc/lib/
+	cp libc/libc.a $(PREFIX)/tools/agbcc/lib/
+	
diff --git a/build.sh b/build.sh
index a1671fd..db2a948 100755
--- a/build.sh
+++ b/build.sh
@@ -1,29 +1,28 @@
 #!/bin/sh
+
 set -e
 CCOPT=
 CXXOPT=
 
-# error if devkitarm is not installed and binutils-arm-none-eabi is not installed
-if ! ([ -n "$DEVKITARM" ] && [ -d "$DEVKITARM/bin" ]) && ! (command -v arm-none-eabi-as &> /dev/null && command -v arm-none-eabi-ar &> /dev/null) ; then
-	echo "Could not find a binutils installation! Re-read the instructions and make sure you've installed either devkitARM or binutils-arm-none-eabi, depending on your system."
-	exit 1
-fi
-
 if [ ! -z "$CC" ]; then CCOPT=CC=$CC; fi
 if [ ! -z "$CXX" ]; then CXXOPT=CXX=$CXX; fi
-make -C gcc clean
-make -C gcc old $CCOPT $CXXOPT
-mv gcc/old_agbcc .
-make -C gcc clean
-make -C gcc $CCOPT $CXXOPT
-mv gcc/agbcc .
+
+mkdir -p build_old_agbcc
+srcdir=../gcc make -C build_old_agbcc -f ../gcc/Makefile clean
+srcdir=../gcc make -C build_old_agbcc -f ../gcc/Makefile old $CCOPT $CXXOPT
+
+mkdir -p build_agbcc
+srcdir=../gcc make -C build_agbcc -f ../gcc/Makefile clean
+srcdir=../gcc make -C build_agbcc -f ../gcc/Makefile normal $CCOPT $CXXOPT
+
 # not sure if the ARM compiler is the old one or the new one (-DOLD_COMPILER)
-rm -f gcc_arm/config.status gcc_arm/config.cache
-cd gcc_arm && ./configure --target=arm-elf --host=i386-linux-gnu && make cc1 && cd ..
-mv gcc_arm/cc1 agbcc_arm
+# || true is needed to keep going if the distclean fails, such as when no configure has been done before
+make -C gcc_arm distclean || true
+cd gcc_arm && ./configure --target=arm-elf --host=i386-linux-gnu && cd ..
+make -C gcc_arm cc1
+
 make -C libgcc clean
 make -C libgcc $CCOPT $CXXOPT
-mv libgcc/libgcc.a .
+
 make -C libc clean
 make -C libc $CCOPT $CXXOPT
-mv libc/libc.a .
diff --git a/gcc/Makefile b/gcc/Makefile
index 9756e90..abba727 100644
--- a/gcc/Makefile
+++ b/gcc/Makefile
@@ -19,12 +19,12 @@
 #Boston MA 02111-1307, USA.
 
 # Directory where sources are, from where we are.
-srcdir = .
+srcdir ?= .
 VPATH = $(srcdir)
 
 CC = gcc
 
-BASE_CFLAGS = -g -std=gnu11 -Werror-implicit-function-declaration
+BASE_CFLAGS = -g -std=gnu11
 
 INCLUDES = -I. -I$(srcdir)
 
@@ -81,7 +81,7 @@ $(OBJS): %.o: %.c $(DEPDIR)/%.d | $(GENERATED)
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-$(RTL_OBJS) $(RTLANAL_OBJS) $(PRINT_OBJS): %.o: %.c $(DEPDIR)/%.d
+$(RTL_OBJS) $(RTLANAL_OBJS) $(PRINT_OBJS): %.o: %.c $(DEPDIR)/%.d genrtl.h
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc_arm/Make-hooks b/gcc_arm/Make-hooks
deleted file mode 100644
index 1fa9bbd..0000000
--- a/gcc_arm/Make-hooks
+++ /dev/null
@@ -1,21 +0,0 @@
-lang.all.build: 
-lang.all.cross: 
-lang.start.encap: 
-lang.rest.encap: 
-lang.info: 
-lang.dvi: 
-lang.install-normal: 
-lang.install-common: 
-lang.install-info: 
-lang.install-man: 
-lang.uninstall: 
-lang.distdir: 
-lang.mostlyclean: 
-lang.clean: 
-lang.distclean: 
-lang.extraclean: 
-lang.maintainer-clean: 
-lang.stage1: 
-lang.stage2: 
-lang.stage3: 
-lang.stage4: 
diff --git a/gcc_arm/Make-host b/gcc_arm/Make-host
deleted file mode 100644
index e69de29..0000000
diff --git a/gcc_arm/Make-lang b/gcc_arm/Make-lang
deleted file mode 100644
index e69de29..0000000
diff --git a/gcc_arm/Make-target b/gcc_arm/Make-target
deleted file mode 100644
index b57eeca..0000000
--- a/gcc_arm/Make-target
+++ /dev/null
@@ -1,35 +0,0 @@
-CROSS_LIBGCC1 = libgcc1-asm.a
-LIB1ASMSRC = arm/lib1funcs.asm
-# CYGNUS LOCAL interworking
-LIB1ASMFUNCS = _udivsi3 _divsi3 _umodsi3 _modsi3 _dvmd_tls _call_via_rX
-# END CYGNUS LOCAL interworking
-
-# These are really part of libgcc1, but this will cause them to be
-# built correctly, so...
-
-LIB2FUNCS_EXTRA = fp-bit.c dp-bit.c
-
-fp-bit.c: $(srcdir)/config/fp-bit.c
-	echo '#define FLOAT' > fp-bit.c
-	echo '#ifndef __ARMEB__' >> fp-bit.c
-	echo '#define FLOAT_BIT_ORDER_MISMATCH' >> fp-bit.c
-	echo '#endif' >> fp-bit.c
-	cat $(srcdir)/config/fp-bit.c >> fp-bit.c
-
-dp-bit.c: $(srcdir)/config/fp-bit.c
-	echo '#ifndef __ARMEB__' > dp-bit.c
-	echo '#define FLOAT_BIT_ORDER_MISMATCH' >> dp-bit.c
-	echo '#define FLOAT_WORD_ORDER_MISMATCH' >> dp-bit.c
-	echo '#endif' >> dp-bit.c
-	cat $(srcdir)/config/fp-bit.c >> dp-bit.c
-
-# CYGNUS LOCAL
-MULTILIB_OPTIONS  = mlittle-endian/mbig-endian mhard-float/msoft-float mapcs-32/mapcs-26 mno-thumb-interwork/mthumb-interwork fno-leading-underscore/fleading-underscore mcpu=arm7
-MULTILIB_DIRNAMES = le be fpu soft 32bit 26bit normal interwork elf under nofmult
-MULTILIB_EXCEPTIONS = *mapcs-26/*mthumb-interwork* *mthumb-interwork*/*mcpu=arm7*
-MULTILIB_MATCHES     = mbig-endian=mbe mlittle-endian=mle mcpu?arm7=mcpu?arm7d mcpu?arm7=mcpu?arm7di mcpu?arm7=mcpu?arm70 mcpu?arm7=mcpu?arm700 mcpu?arm7=mcpu?arm700i mcpu?arm7=mcpu?arm710 mcpu?arm7=mcpu?arm710c mcpu?arm7=mcpu?arm7100 mcpu?arm7=mcpu?arm7500 mcpu?arm7=mcpu?arm7500fe mcpu?arm7=mcpu?arm6 mcpu?arm7=mcpu?arm60 mcpu?arm7=mcpu?arm600 mcpu?arm7=mcpu?arm610 mcpu?arm7=mcpu?arm620
-LIBGCC = stmp-multilib
-INSTALL_LIBGCC = install-multilib
-# END CYGNUS LOCAL
-
-TARGET_LIBGCC2_CFLAGS = -Dinhibit_libc
diff --git a/gcc_arm/config.h b/gcc_arm/config.h
deleted file mode 100644
index 0c48f96..0000000
--- a/gcc_arm/config.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#include "auto-host.h"
-#include "gansidecl.h"
-#include "i386/xm-i386.h"
-#ifndef HAVE_ATEXIT
-#define HAVE_ATEXIT
-#endif
-#ifndef POSIX
-#define POSIX
-#endif
-#ifndef BSTRING
-#define BSTRING
-#endif
diff --git a/gcc_arm/cstamp-h b/gcc_arm/cstamp-h
deleted file mode 100644
index 8b13789..0000000
--- a/gcc_arm/cstamp-h
+++ /dev/null
@@ -1 +0,0 @@
-
diff --git a/gcc_arm/gencheck.h b/gcc_arm/gencheck.h
deleted file mode 100644
index e69de29..0000000
diff --git a/gcc_arm/hconfig.h b/gcc_arm/hconfig.h
deleted file mode 100644
index 0c48f96..0000000
--- a/gcc_arm/hconfig.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#include "auto-host.h"
-#include "gansidecl.h"
-#include "i386/xm-i386.h"
-#ifndef HAVE_ATEXIT
-#define HAVE_ATEXIT
-#endif
-#ifndef POSIX
-#define POSIX
-#endif
-#ifndef BSTRING
-#define BSTRING
-#endif
diff --git a/gcc_arm/options.h b/gcc_arm/options.h
deleted file mode 100644
index e69de29..0000000
diff --git a/gcc_arm/specs.h b/gcc_arm/specs.h
deleted file mode 100644
index e69de29..0000000
diff --git a/gcc_arm/tconfig.h b/gcc_arm/tconfig.h
deleted file mode 100644
index 1fa5d1e..0000000
--- a/gcc_arm/tconfig.h
+++ /dev/null
@@ -1,2 +0,0 @@
-#include "gansidecl.h"
-#include "arm/xm-arm.h"
diff --git a/gcc_arm/tm.h b/gcc_arm/tm.h
deleted file mode 100644
index bda15db..0000000
--- a/gcc_arm/tm.h
+++ /dev/null
@@ -1,3 +0,0 @@
-#define TARGET_CPU_DEFAULT (TARGET_CPU_generic)
-#include "gansidecl.h"
-#include "arm/unknown-elf.h"
diff --git a/install.sh b/install.sh
index 637a21d..67ad4dd 100755
--- a/install.sh
+++ b/install.sh
@@ -6,13 +6,13 @@ if [ "$1" != "" ]; then
 		mkdir -p $1/tools/agbcc/bin
 		mkdir -p $1/tools/agbcc/include
 		mkdir -p $1/tools/agbcc/lib
-		cp agbcc $1/tools/agbcc/bin/
-		cp old_agbcc $1/tools/agbcc/bin/
-		cp agbcc_arm $1/tools/agbcc/bin/
+		cp build_agbcc/agbcc $1/tools/agbcc/bin/
+		cp build_old_agbcc/old_agbcc $1/tools/agbcc/bin/
+		cp gcc_arm/cc1 $1/tools/agbcc/bin/agbcc_arm
 		cp -R libc/include $1/tools/agbcc/ #drop include, because we don't want include/include
 		cp ginclude/* $1/tools/agbcc/include/
-		cp libgcc.a $1/tools/agbcc/lib/
-		cp libc.a $1/tools/agbcc/lib/
+		cp libgcc/libgcc.a $1/tools/agbcc/lib/
+		cp libc/libc.a $1/tools/agbcc/lib/
 		echo "agbcc successfully installed!"
 	else
 		if [ -d "../$1" ]; then
diff --git a/libc/Makefile b/libc/Makefile
index d9de489..0fef62d 100644
--- a/libc/Makefile
+++ b/libc/Makefile
@@ -9,17 +9,24 @@ else
 DKA_EXISTS=0
 endif
 
-ifneq ($(DKA_EXISTS),1)
 PREFIX := arm-none-eabi-
 export AR := $(PREFIX)ar
 export AS := $(PREFIX)as
+
+ifeq ($(DKA_EXISTS),0)
+ifeq ($(shell which $(AR)),)
+$(info DKA_EXISTS=$(DKA_EXISTS))
+$(info DEVKITARM=$(DEVKITARM))
+$(info which arm-none-eabi-ar is $(shell which arm-none-eabi-ar))
+$(error Cannot find $(AR) or devkitARM, make sure you have an arm-none-eabi toolchain or devkitARM installed and your environment variables properly set up)
+endif
 endif
 
 SHELL := /bin/bash -o pipefail
 
 ASFLAGS := -mcpu=arm7tdmi
 
-CC1    := ../old_agbcc
+CC1    := ../build_old_agbcc/old_agbcc
 CFLAGS := -O2 -fno-builtin
 
 CPPFLAGS := -I ../ginclude -I include -nostdinc -undef \
diff --git a/libgcc/Makefile b/libgcc/Makefile
index 0e96527..d46bd84 100644
--- a/libgcc/Makefile
+++ b/libgcc/Makefile
@@ -9,17 +9,24 @@ else
 DKA_EXISTS=0
 endif
 
-ifneq ($(DKA_EXISTS),1)
 PREFIX := arm-none-eabi-
 export AR := $(PREFIX)ar
 export AS := $(PREFIX)as
+
+ifeq ($(DKA_EXISTS),0)
+ifeq ($(shell which $(AR)),)
+$(info DKA_EXISTS=$(DKA_EXISTS))
+$(info DEVKITARM=$(DEVKITARM))
+$(info which arm-none-eabi-ar is $(shell which arm-none-eabi-ar))
+$(error Cannot find $(AR) or devkitARM, make sure you have an arm-none-eabi toolchain or devkitARM installed and your environment variables properly set up)
+endif
 endif
 
-CC1 = ../old_agbcc
+CC1 = ../build_old_agbcc/old_agbcc
 
 libgcc.a: libgcc1.a libgcc2.a fp-bit.o dp-bit.o
-	$(AR) -x libgcc1.a;
-	$(AR) -x libgcc2.a;
+	$(AR) -x libgcc1.a
+	$(AR) -x libgcc2.a
 	$(AR) -rc libgcc.a *.o
 
 LIB1ASMFUNCS = _udivsi3 _divsi3 _umodsi3 _modsi3 _dvmd_tls _call_via_rX
@@ -66,19 +73,19 @@ libgcc2.a: libgcc2.c longlong.h
 	mv tmplibgcc2.a libgcc2.a
 
 fp-bit.o: fp-bit.c
-	$(CPP) -undef -I ../ginclude -nostdinc -o fp-bit.i fp-bit.c;
+	$(CPP) -undef -I ../ginclude -nostdinc -o fp-bit.i fp-bit.c
 	$(CC1) -O2 fp-bit.i
 	rm -f fp-bit.i
 	bash -c 'echo -e ".text\n\t.align\t2, 0\n"' >> fp-bit.s
-	$(AS) -mcpu=arm7tdmi -o fp-bit.o fp-bit.s;
+	$(AS) -mcpu=arm7tdmi -o fp-bit.o fp-bit.s
 	rm -f fp-bit.s
 
 dp-bit.o: dp-bit.c
-	$(CPP) -undef -I ../ginclude -nostdinc -o dp-bit.i dp-bit.c;
+	$(CPP) -undef -I ../ginclude -nostdinc -o dp-bit.i dp-bit.c
 	$(CC1) -O2 dp-bit.i
 	rm -f dp-bit.i
 	bash -c 'echo -e ".text\n\t.align\t2, 0\n"' >> dp-bit.s
-	$(AS) -mcpu=arm7tdmi -o dp-bit.o dp-bit.s;
+	$(AS) -mcpu=arm7tdmi -o dp-bit.o dp-bit.s
 	rm -f dp-bit.s
 
 fp-bit.c: fp-bit-base.c
@@ -94,4 +101,4 @@ dp-bit.c: fp-bit-base.c
 .PHONY: clean
 
 clean:
-	rm -f *.o *.a *.s *.i
\ No newline at end of file
+	rm -f *.o *.a *.s *.i