diff --git a/Makefile b/Makefile
index 86e054e..2de7386 100644
--- a/Makefile
+++ b/Makefile
@@ -15,32 +15,32 @@ endif
 
 all:
 ifeq ($(OS), Windows_NT)
-	@(objdump -a $(BINARY) 2> /dev/null | grep "pei-i386" > /dev/null || make --no-print-directory clean; exit 0)
+	@(objdump -a $(BINARY) 2> /dev/null | grep "pei-i386" > /dev/null || ${MAKE} --no-print-directory clean; exit 0)
 endif
-	@make --no-print-directory $(BINARY)
+	@${MAKE} --no-print-directory $(BINARY)
 
 64:
 ifeq ($(OS), Windows_NT)
-	@(objdump -a $(BINARY) 2> /dev/null | grep "pei-i386" > /dev/null && make --no-print-directory clean; exit 0)
-	@make --no-print-directory $(BINARY) 64=1
+	@(objdump -a $(BINARY) 2> /dev/null | grep "pei-i386" > /dev/null && ${MAKE} --no-print-directory clean; exit 0)
+	@${MAKE} --no-print-directory $(BINARY) 64=1
 else
-	@make --no-print-directory $(BINARY)
+	@${MAKE} --no-print-directory $(BINARY)
 endif
 
 clean:
 	rm -rf $(BINARY) $(CLEAN) crcutil.a *.o *.exe test.bin d1aa92b05d1f2638f423661ae4735446.bin
 
 mrproper:
-	@make --no-print-directory clean
+	@${MAKE} --no-print-directory clean
 	rm -rf test.bin *.tar.gz *.zip $(DISTNAME)-bin-win32 $(DISTNAME)-bin-win64
 
 dist:
-	make mrproper
+	${MAKE} mrproper
 	(cd ..; tar -cz --numeric-owner -f $(DISTNAME).tar.gz $(DISTNAME))
 	mv ../$(DISTNAME).tar.gz .
 ifeq ($(OS), Windows_NT)
 	mkdir $(DISTNAME)-bin-win32
-	make all
+	${MAKE} all
 	cp $(BINARY) $(DISTNAME)-bin-win32
 	cp README $(DISTNAME)-bin-win32/README.txt
 	cp COPYING $(DISTNAME)-bin-win32/COPYING.txt
@@ -48,9 +48,9 @@ ifeq ($(OS), Windows_NT)
 	unix2dos $(DISTNAME)-bin-win32/COPYING.txt
 	zip -r $(DISTNAME)-bin-win32.zip $(DISTNAME)-bin-win32
 	rm -rf $(DISTNAME)-bin-win32
-	make clean
+	${MAKE} clean
 	mkdir $(DISTNAME)-bin-win64
-	make all 64=1
+	${MAKE} all 64=1
 	cp $(BINARY) $(DISTNAME)-bin-win64
 	cp README $(DISTNAME)-bin-win64/README.txt
 	cp COPYING $(DISTNAME)-bin-win64/COPYING.txt
@@ -58,7 +58,7 @@ ifeq ($(OS), Windows_NT)
 	unix2dos $(DISTNAME)-bin-win64/COPYING.txt
 	zip -r $(DISTNAME)-bin-win64.zip $(DISTNAME)-bin-win64
 	rm -rf $(DISTNAME)-bin-win64
-	make clean
+	${MAKE} clean
 endif
 
 test: $(BINARY) test.bin
@@ -69,12 +69,12 @@ test: $(BINARY) test.bin
 	@sh -c "time ./$(BINARY) test.bin 1000000 13fbda0d"
 
 $(BINARY): findcrcs.cc md5.c md5.h crcutil-1.0 crcutil.a
-	$(BINPREFIX)g++ -O3 -D_FILE_OFFSET_BITS=64 -Wall -o $@ $(EXEFLAGS) findcrcs.cc md5.c crcutil.a -Icrcutil-1.0/code -Icrcutil-1.0/examples
+	$(BINPREFIX)g++ -O3 -D_FILE_OFFSET_BITS=64 -Wall -o $@ $(EXEFLAGS) $(CXXFLAGS) $(LDFLAGS) findcrcs.cc md5.c crcutil.a -Icrcutil-1.0/code -Icrcutil-1.0/examples
 	$(BINPREFIX)strip -s $@
 
 crcutil.a: crcutil-1.0
 	rm -rf *.o
-	$(BINPREFIX)g++ -O3 -Wall -mcrc32 -c crcutil-1.0/examples/interface.cc crcutil-1.0/code/*.cc -Icrcutil-1.0/code -Icrcutil-1.0/tests -Icrcutil-1.0/examples
+	$(BINPREFIX)g++ -O3 -Wall $(CXXFLAGS) -c crcutil-1.0/examples/interface.cc crcutil-1.0/code/*.cc -Icrcutil-1.0/code -Icrcutil-1.0/tests -Icrcutil-1.0/examples
 	$(BINPREFIX)ar r crcutil.a *.o
 	rm -rf *.o
 
diff --git a/findcrcs.cc b/findcrcs.cc
index 87863ef..7b97e93 100644
--- a/findcrcs.cc
+++ b/findcrcs.cc
@@ -33,6 +33,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <stdlib.h>