portable: configure: split out dependencies Rather than assume all dependencies are required for all programs, split them out. This will make packaging easier, as well as splitting the code to use subprojects. Note that due to the use of config.h semantics, in most cases the got_compat.h header file is now at the top of the .c file it is included in, so that it can handle the system header inclusion properly.

portable: Makefile: add -Wno-pointer-sign Ignore warnings about pointer-signedness. This may well get fixed upstream, but won't hurt to be left here, regardless.

portable: gotwebd: use template This updates -portable's gotwebd instance to make use of the new templating engine.

portable: sync CFLAGS with upstream Due to the way the Makefiles are structured, there is no direct mapping between upstream and how -portable provides the same functionality. Therefore, add -Wunused-variable and -Wwrite-strings as per previous commits.

portable: propagate AM_CFLAGS/AM_CPPFLAGS Allow for warnings via AM_CFLAGS in a common Makefile, and let those values propagate to all other Makefiles. Currently the more useful checks are disabled until upstream changes are made to reduce warnings. While here, also fix the version string to remove quotes.