[LLVMdev] proposal to avoid zlib dependency.

[Mueller-Roemer, Johannes Sebastian]

I'll have another look tomorrow.

IMO, it is unnecessary clutter. It will fail if ${ZLIB_LIBRARIES} or ${ZLIB_INCLUDE_DIRS} are used anyways as they will be set to NOTFOUND. Or we go back to a silent-fail solution:

find_package(ZLIB QUIET)
if (LLVM_ENABLE_ZLIB AND ZLIB_FOUND)
  set(HAVE_ZLIB_H 1)
  set(HAVE_LIBZ 1)
  list(APPEND CMAKE_REQUIRED_LIBRARIES ${ZLIB_LIBRARIES})
  list(APPEND CMAKE_REQUIRED_INCLUDES ${ZLIB_INCLUDE_DIRS})
else()
  set(HAVE_ZLIB_H 0)
  set(HAVE_LIBZ 0)
endif()

--
Johannes S. Mueller-Roemer, MSc
Wiss. Mitarbeiter - Interactive Engineering Technologies (IET)

Fraunhofer-Institut für Graphische Datenverarbeitung IGD
Fraunhoferstr. 5  |  64283 Darmstadt  |  Germany
Tel +49 6151 155-606  |  Fax +49 6151 155-139
johannes.mueller-roemer at igd.fraunhofer.de  |  www.igd.fraunhofer.de


-----Original Message-----
From: Dan Liew [mailto:dan at su-root.co.uk] 
Sent: Wednesday, September 17, 2014 17:26
To: Mueller-Roemer, Johannes Sebastian
Cc: llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] proposal to avoid zlib dependency.

On 17 September 2014 15:47, Mueller-Roemer, Johannes Sebastian <Johannes.Sebastian.Mueller-Roemer at igd.fraunhofer.de> wrote:
> It's half the way there. Configuring and compiling works, but linking fails, probably some definition mismatches...

It configured, compiled and linked okay for me. Could you look into it?

>
> But it can definitely be simplified, as due to the "REQUIRED" flag 
> CMake will already fail if zlib isn't found, so no need for the
>
>   if (ZLIB_FOUND)
>     ...
>   else()
>     message(FATAL_ERROR "zlib was requested but it could not be found")
>   endif()
>

Thanks. I'm aware that's what REQUIRED would do but I thought I'd try to be "defensive" just in case someone later on thinks removing "REQUIRED" is a good idea...

If you think its unnecessary clutter I'd happily remove it.