util.dbuffer: Add efficient shortcuts for discard() in certain cases
If the buffer is already empty, nothing to do. If we're throwing away the
whole buffer, we can just empty it and avoid read_chunk() (which in turn
may collapse()). These shortcuts are much more efficient.
.DEFAULT: localhost.crt
keysize=2048
# How to:
# First, `make yourhost.cnf` which creates a openssl config file.
# Then edit this file and fill in the details you want it to have,
# and add or change hosts and components it should cover.
# Then `make yourhost.key` to create your private key, you can
# include keysize=number to change the size of the key.
# Then you can either `make yourhost.csr` to generate a certificate
# signing request that you can submit to a CA, or `make yourhost.crt`
# to generate a self signed certificate.
${.TARGETS:M*.crt}:
openssl req -new -x509 -newkey rsa:$(keysize) -nodes -keyout ${.TARGET:R}.key \
-days 365 -sha256 -out $@ -utf8 -subj /CN=${.TARGET:R}
.SUFFIXES: .key .crt