Turn up compiler warnings to max and fix them; one more indefinite length test
diff --git a/Makefile b/Makefile
index c739908..6e7745f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-CFLAGS=-I inc -I test -Os
+CFLAGS=-I inc -I test -Os -Wall -Werror -pedantic-errors -Wextra -Wshadow
 
 QCBOR_OBJ=src/UsefulBuf.o src/qcbor_encode.o src/qcbor_decode.o src/ieee754.o