Add code to parse a debug category string

Use strdup to be able to use strtok on the category string and add
a test case. Also safe some more information to be able to use color
in the print statement.
diff --git a/configure.in b/configure.in
index 034972a..d4902d6 100644
--- a/configure.in
+++ b/configure.in
@@ -21,5 +21,6 @@
     include/Makefile
     src/Makefile
     tests/Makefile
+    tests/debug/Makefile
     tests/timer/Makefile
     Makefile)