Switched to xz archives for smaller size.

Removed upstreamed patches.

Reorganized Makefile a little bit for clarity. Build/Prepare is not useful
anymore. Upstream converted the file to LF.

Refreshed config.

Removed -ansi option from the original CFLAGS as this was causing long
long support to be missing.

Removed fPIC. We have the macro $(FPIC) already used. No point in setting
fpic and fPIC together.

Removed pedantic -Wlong-long warnings as they are not useful.

Removed -std=gnu++98. Not only is it unnecessary (it compiles against all
standards), it actually results in a size increase. 75843 vs. 75222 (gcc
in OpenWrt defaults to g++14).

Added --gc-sections to linker flags to reduce size: 72653 vs 75222.

Removed warn linker options. They have been upstreamed.

Tested on Archer C7v2 and GnuBee PC1.

Signed-off-by: Rosen Penev <rosenp@gmail.com>