Find documentation etc. on this patch under
	http://free.acrconsulting.co.uk/
diff -Nru serialmail-0.75/conf-cc serialmail-0.75_cc_clean/conf-cc
--- serialmail-0.75/conf-cc	1998-11-15 02:28:23.000000000 +0000
+++ serialmail-0.75_cc_clean/conf-cc	2010-02-11 23:03:06.000000000 +0000
@@ -1,3 +1,3 @@
-gcc -O2
+gcc -O2 -include /usr/include/errno.h
 
 This will be used to compile .c files.
diff -Nru serialmail-0.75/Makefile serialmail-0.75_cc_clean/Makefile
--- serialmail-0.75/Makefile	1998-11-15 02:28:23.000000000 +0000
+++ serialmail-0.75_cc_clean/Makefile	2010-02-11 23:04:30.000000000 +0000
@@ -101,6 +101,10 @@
 it instcheck
 	./instcheck
 
+clean: \
+TARGETS
+	rm -f `cat TARGETS`
+
 compile: \
 warn-auto.sh conf-cc
 	( cat warn-auto.sh; \