diff --git a/.gitignore b/.gitignore
index 70fa0ca..27d0639 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,10 +1,3 @@
-print
-print_aarch64
-print_mips32
-print_x64
-bldtst
-bldtst_aarch64
-bldtst_mips32
-bldtst_x64
-bldtst_llvm
 a.out
+bin
+tmp
diff --git a/Makefile b/Makefile
index 8944fcb..5b361b8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,32 +1,45 @@
+bindir ?= ./bin
+
+CFLAGS := -nostdlib -static -fuse-ld=lld -fno-stack-protector
+
+CLANG_WNO := -Wno-incompatible-library-redeclaration
+GCC_WNO := -Wno-builtin-declaration-mismatch
+
+MIPS_CFLAGS := --target=mips-linux-gnu -fno-pic
+MIPSEL_CFLAGS := --target=mipsel-linux-gnu -fno-pic
+X86_64_CFLAGS := --target=x86_64-linux-gnu
+
+AARCH64_CFLAGS := --target=aarch64-linux-gnu
+
 all: buildtest
 
 clean: 
-	if test -f print; then rm print; fi
-	if test -f print_x64; then rm print_x64; fi
-	if test -f print_aarch64; then rm print_aarch64; fi
-	if test -f print_mips32; then rm print_mips32; fi
-	if test -f bldtst; then rm bldtst; fi
-	if test -f bldtst_llvm; then rm bldtst_llvm; fi
-	if test -f bldtst_x64; then rm bldtst_x64; fi
-	if test -f bldtst_aarch64; then rm bldtst_aarch64; fi
-	if test -f bldtst_mips32; then rm bldtst_mips32; fi
+	rm $(bindir)/*
 
-buildtest: bldtst bldtst_llvm bldtst_x64 bldtst_aarch64 bldtst_mips32
+$(bindir)/:
+	mkdir -p ${bindir}
 
-.PHONY: all buildtest clean
+headers := sys.h int.h
+buildtest: $(bindir)/bldtst $(bindir)/bldtst_llvm $(bindir)/bldtst_x64 $(bindir)/bldtst_aarch64 $(bindir)/bldtst_mips $(bindir)/bldtst_mipsel
 
 
-bldtst: buildtest.c arch/*.c
-	gcc -static -nostdlib -Wno-builtin-declaration-mismatch -fno-stack-protector -o bldtst buildtest.c arch/*.c
+.PHONY: all clean buildtest
 
-bldtst_llvm: buildtest.c arch/*.c
-	clang -nostdlib -Wno-incompatible-library-redeclaration -static -fuse-ld=lld -fno-stack-protector -o bldtst_llvm buildtest.c arch/*.c
 
-bldtst_x64: buildtest.c arch/x86_64.c
-	clang --target=x86_64-linux-gnu -nostdlib -Wno-incompatible-library-redeclaration -static -fuse-ld=lld -fno-stack-protector -o bldtst_x64 buildtest.c arch/x86_64.c
+${bindir}/bldtst: buildtest.c $(headers) arch/* | $(bindir)/
+	gcc $(CFLAGS) $(GCC_WNO) -o $@ buildtest.c arch/*.c
 
-bldtst_aarch64: buildtest.c arch/aarch64.c
-	clang --target=aarch64-linux-gnu -nostdlib -Wno-incompatible-library-redeclaration -static -fuse-ld=lld -fno-stack-protector -o bldtst_aarch64 buildtest.c arch/aarch64.c
+${bindir}/bldtst_llvm: $(headers) buildtest.c arch/* | $(bindir)/
+	clang $(CFLAGS) $(CLANG_WNO) -o $@ buildtest.c arch/*.c
 
-bldtst_mips32: buildtest.c arch/mips.c
-	clang --target=mips-linux-gnu -nostdlib -Wno-incompatible-library-redeclaration -static -fuse-ld=lld -fno-stack-protector -fno-pic -o bldtst_mips32 buildtest.c arch/mips.c
+${bindir}/bldtst_x64: $(headers) buildtest.c arch/x86_64.c arch/generic.h | $(bindir)/
+	clang $(X86_64_CFLAGS) $(CFLAGS) $(CLANG_WNO) -o $@ buildtest.c arch/x86_64.c
+
+${bindir}/bldtst_aarch64: $(headers) buildtest.c arch/aarch64.c arch/generic.h | $(bindir)/
+	clang $(AARCH64_CFLAGS) $(CFLAGS) $(CLANG_WNO) -o $@ buildtest.c arch/aarch64.c
+
+${bindir}/bldtst_mips: $(headers) buildtest.c arch/mips.c arch/generic.h | $(bindir)/
+	clang $(MIPS_CFLAGS) $(CFLAGS) $(CLANG_WNO) -o $@ buildtest.c arch/mips.c
+
+${bindir}/bldtst_mipsel: $(headers) buildtest.c arch/mips.c arch/generic.h | $(bindir)/
+	clang $(MIPSEL_CFLAGS) $(CFLAGS) $(CLANG_WNO) -o $@ buildtest.c arch/mips.c