Add -e flag to explain what the previous smiley face means. This

requires us to also know what the previous return signal is, so
if XD is given a return code, it passes it through when finishing
execution.

Makefile

@@ -2,7 +2,7 @@ include config.mk
 
 # flags and incs
 PKGS = $(GITLIB)
-CFLAGS = -DVERSION=\"$(VERSION)\" -Wall -pedantic -O3 $(GIT) $(ERR)
+CFLAGS = -DVERSION=\"$(VERSION)\" -Wall -pedantic -O3 $(GIT) $(ERR) $(EXPLAIN)
 LIBS = `$(PKG_CONFIG) --libs --cflags $(PKGS)`
 
 all: XD