Remove unused functions from cvg

Begin cvg

add a separate compile-time DEBUG flag for the delta cache

add dedicated compilation flag for the delta cache, separate from object cache

build with -Wwrite-strings Throwing this into the mix for a while, we can always get rid of it again if it becomes annoying. No objections from stsp@

build with -Wmissing-prototypes ok stsp@

merge new diff implementation from the diff.git repository This new diff implementation was started by Neels Hofmeyr during the u2k20 hackathon and now replaces diffreg.c code lifted from the OpenBSD base system. The integration of this code into Got was done by me. Got now uses the patience diff algorithm by default. The diff.git repository will remain the primary repository for the diff code, which already compiles and runs on other operating systems such as Linux. Any fixes and improvements for files inherited from the diff.git repository should be written against that repository and synced to got.git afterwards.

disable compiler warnings in release builds because -Werror is bad for ports sthen@ suggested to drop -Werror; I think we don't need any -W in release mode

ensure that we always install static binaries to gotweb's chroot Compile static libexec binaries for gotweb, keeping them separate from the main build. Use the same source files but a separate set of Makefiles. Previously, 'make web-install' installed whichever libexec binaries had already been built, and if those happened to be dynamically linked they failed to run inside the chroot which resulted in "privsep peer process closed pipe" being rendered on the index page.

link just gotweb with kcgi, not the libexec helpers

create dir for public repos during 'make web-install'; avoids an unveil error

remove examples file

kn@ and stsp@ suggested changes

blame css

save blame work