Not all of them :-(
> nimble install zlib
zlib not found in local packages.json, check internet for updated packages? [y/N]
>nimble install libzip
libzip not found in local packages.json, check internet for updated packages? [y/N]
you can just use {.importc, dynlib:...} and the compiler will import the function without actually #including the header. Essentially when you use {.header.} the compiler can generate names that conflict with stuff in the header, most C libs are pretty good about prefixing their functions but the #include inserted is transitive. Also if the nim compiler knows about all the symbols in your module it will generate perfect forward declarations in C and this makes compiling your code faster.
Also note that dnylib does not actually introduce a dependency on the dll/so any more than {.header.} does, you still need the library (either static or dynamic) with header and you can get static linkage using --dynlibOverride
Not all of them
Uh, sorry about that. I will add them to Nimble as soon as possible.