[sdl2] Fix pkgconfig: missing system libs

[gdxn96]

CMake Error at scripts/cmake/vcpkg_fixup_pkgconfig.cmake:232 (message):
  Library "glib-2.0" was not found! If it is a system library use the
  SYSTEM_LIBRARIES parameter for the vcpkg_fixup_pkgconfig call! Otherwise,
  correct the *.pc file
Call Stack (most recent call first):
  scripts/cmake/vcpkg_fixup_pkgconfig.cmake:298 (vcpkg_fixup_pkgconfig_check_files)
  ports/sdl2/portfile.cmake:97 (vcpkg_fixup_pkgconfig)
  scripts/ports.cmake:79 (include)

• Above traceback encountered for all of the following libraries glib-2.0 gobject-2.0 gio-2.0 ibus-1.0

• Fixes [sdl2[core]:x64-linux] build failure #13236

[ghost]

All CLA requirements met.

[ras0219]

Hi @gdxn96, thanks for the PR!

Could you try the branch in #13126 and see if that solves your issue? If not, could you please post the contents of the .pc files here?

Because glib is packaged inside vcpkg, we don't want to directly link the system glib accidentally.

[gdxn96]

@ras0219 @JackBoosY unfortunately that branch did not fix the glib issue

-- Building x64-linux-rel
-- Fixing pkgconfig file: /home/george/Desktop/git/vcpkg/packages/sdl2_x64-linux/lib/pkgconfig/sdl2.pc
CMake Error at scripts/cmake/vcpkg_fixup_pkgconfig.cmake:136 (message):
  find_library() failed with result: CHECK_LIB_glib-2.0_RELEASE-NOTFOUND

      find_library(CHECK_LIB_glib-2.0_RELEASE NAMES "glib-2.0" PATHS /home/george/Desktop/git/vcpkg/packages/sdl2_x64-linux/lib/pkgconfig/../../lib "/home/george/Desktop/git/vcpkg/installed/x64-linux/lib" NO_DEFAULT_PATH)
Call Stack (most recent call first):
  scripts/cmake/vcpkg_fixup_pkgconfig.cmake:234 (vcpkg_fixup_pkgconfig_check_files)
  ports/sdl2/portfile.cmake:97 (vcpkg_fixup_pkgconfig)
  scripts/ports.cmake:79 (include)


Error: Building package sdl2:x64-linux failed with: BUILD_FAILED
Please ensure you're using the latest portfiles with `./vcpkg update`, then
submit an issue at https://github.com/Microsoft/vcpkg/issues including:
  Package: sdl2:x64-linux
  Vcpkg version: 2020.06.15-unknownhash

sdl2.pc file

prefix=${pcfiledir}/../..
# sdl pkg-config source file

exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

Name: sdl2
Description: Simple DirectMedia Layer is a cross-platform multimedia library designed to provide low level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL, and 2D video framebuffer.
Version: 2.0.12
Requires:
Conflicts:
Libs: -L"${libdir}" -Wl,-rpath,${libdir} -Wl,--enable-new-dtags -pthread -lSDL2  -lglib-2.0 -lgobject-2.0 -lgio-2.0 -libus-1.0 -ldbus-1 -l/usr/lib/x86_64-linux-gnu/libsndio.so -ldl -lm  -Wl,--no-undefined -pthread -lSDL2 
Cflags: -I"${includedir}/SDL2"  -D_REENTRANT

[JackBoosY]

Don't know why sdl2 need them.

[gdxn96]

All I know, is SDL2 failed to install locally without this change. Once I added this change it worked fine.

I don't understand Cmake very well so if this change is not appropriate just lmk.

Maybe it's an OS thing? I'm using Ubuntu 20.04, maybe they were previously installed by default and no longer are? (grasping straws)

[JackBoosY]

@gdxn96 Could you provide your broken sdl2.pc?

[gdxn96]

The one I have above? @JackBoosY
If not that one then I'll reset to master and reinstall later tonight to generate another

[gdxn96]

@JackBoosY
broken sdl2.pc

prefix=${pcfiledir}/../..
# sdl pkg-config source file

exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

Name: sdl2
Description: Simple DirectMedia Layer is a cross-platform multimedia library designed to provide low level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL, and 2D video framebuffer.
Version: 2.0.12
Requires:
Conflicts:
Libs: -L${libdir} -Wl,-rpath,${libdir} -Wl,--enable-new-dtags -pthread -lSDL2 
Libs.private: -lglib-2.0 -lgobject-2.0 -lgio-2.0 -libus-1.0 -ldbus-1 -l/usr/lib/x86_64-linux-gnu/libsndio.so -ldl -lm  -Wl,--no-undefined -pthread -lSDL2 
Cflags: -I${includedir}/SDL2  -D_REENTRANT

[ras0219-msft]

I think that this is indicative that we can't expect to list out the full set of system dependencies; it would require us to somehow divine the precise naming and linkage structure of every system out there.

For now, this is blocked on #13126

[jube]

If you install glib from vcpkg, you only have to set ibus-1.0 as a system dependency. So, the patch should be changed to depend on glib and add ibus as a system dependency.

[marcel-ibay]

If you install glib from vcpkg, you only have to set ibus-1.0 as a system dependency. So, the patch should be changed to depend on glib and add ibus as a system dependency.

Was there a documentation on how this could be achieved? It seems more safer than deleting ibus from the host environment.
When I added sdl2 as part of dependencies in vcpkg.json, vcpkg automatically searches for sdl2's dependencies within its ports. How can we add a specific library that are present in the host environment to be used by vcpkg when searching for dependencies?

[jgilje]

Just wanted to add to the discussion as I mistakenly opened an identical PR in #14019

The root issue is that the SDL2 CMakeLists.txt detects that an ibus-1.0 development package is available and uses pkg-config to add fetch linker flags for ibus. The resulting dependencies can be seen by manually running pkg-config on a machine with this package installed (libibus-1.0-dev on an Debian/Ubuntu distro):

$ pkg-config --libs ibus-1.0
-libus-1.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0

The search for Ibus is scoped to only apply to Linux systems. Personally, I'd recommend adding a patch which simply removes the ibus detection lines from SDL2's CMakeLists, and the entire issue at talk here could be closed.

[jgilje]

@jube or @JackBoosY: Seeing there appears to be no further progress here, and I'm keen to get this solved, is it OK for me to open a new PR based on my suggested fix?

[JackBoosY]

@jgilje Sure, please!

[gdxn96]

@jube or @JackBoosY: Seeing there appears to be no further progress here, and I'm keen to get this solved, is it OK for me to open a new PR based on my suggested fix?

If you know what you're doing, please go for it, lord knows I don't 😁