libgphoto2: add new recipe

[sparik]

Specify library name and version: libgphoto2/2.5.27

---

• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the
  conan-center hook activated.

[sparik]

This needs to be added to the KB-H050 whitelist

[madebr]

Please don't use auto. auto might mean yes or no, so it's kinda random.
If a library is not detected when using yes, that means we must help the build system to find it.

[sparik]

I'm not sure that would work. There is no yes option

--with-libcurl=PREFIX where to find libcurl, "no" or "auto"

[sparik]

I think auto here means "try to find it"

[madebr]

I checked the m4 files, and those --with options accept prefixes.
Perhaps you can pass "--with-libcurl={}".format(tools.unix_path(self.deps_cpp_info["libcurl"].rootpath))?
It indeed does not accept yes.

[sparik]

I just tried that, doesn't work. Everything seems to go well except a warning like below:

* Warning:
*   libtool file libxml-2.0.la could not be found.
*   We may be linking against the WRONG library.```

[madebr]

I checked again, and your current approach looks fine after all.
no disabled the functionality, and it will fall back to the pc files.
So LGTM.

[madebr]

This needs to be added to the KB-H050 whitelist

Indeed, libgphoto uses a main library + loadable libraries.
There's no switch to build the main library as a static library, while keep building the loadable libraries as a shared library.

Feel free to add libgphoto2 to the (sorted) list at
https://github.com/conan-io/hooks/blob/9345dda32175f229d41d943dc964e840988d946a/hooks/conan-center.py#L753-L760

[madebr]

You can do: "with-jpeg={}".format(yes_no(self.options.with_libjpeg) and add it to the list above.

[sparik]

Are you sure? ./configure --help does not list with-jpeg as an option

[madebr]

You're right about with-jpeg. It doesn't support yes.
I checked configure.ac and it's behavior is "unsafe".

AC_ARG_WITH([jpeg], AS_HELP_STRING([--without-jpeg], [Build without jpeg library (default: no)]))
AS_IF([test "x$with_jpeg" != "xno"], [
	AC_CHECK_LIB(jpeg,jpeg_start_decompress,[
		AC_CHECK_HEADER(jpeglib.h,[
			AC_DEFINE(HAVE_LIBJPEG,1,[define if we found LIBJPEG and its headers])
			LIBJPEG="-ljpeg"
			libjpeg_msg="yes"
		])
	])
])

If it cannot find the jpeg_start_decompress symbol or find the jpeglib.h header, it fails.
It can potentially not find libjpeg.

[conan-center-bot]

All green in build 4 (31df04986675c12c2a41305db722c9d471feb012):

• libgphoto2/2.5.27@:
  All packages built successfully! (All logs)