Arch Linux

OK, it's possible, that correct PKGBUILD is:

# Maintainer: Antonis Geralis

pkgname=libtmdbqt-git
pkgver=r21.19c5bd9
pkgrel=1
pkgdesc='This library can retrieve information about movies from the Tmdb web service.'
arch=('i686' 'x86_64')
url='https://projects.kde.org/projects/kde/kde-workspace'
license=('GPL')
depends=('qt5-base')
makedepends=('git')
optdepends=()
conflicts=('libtmdbqt')
provides=('libtmdbqt')
source=("git://anongit.kde.org/libtmdbqt.git")
#install=$pkgname.install
sha256sums=('SKIP')

pkgver() {
cd libtmdbqt
printf "r%s.%s" "$(git rev-list --count HEAD)" "$(git rev-parse --short HEAD)"
}

prepare() {
mkdir -p build
}

build() {
cd build
cmake ../libtmdbqt \
-DCMAKE_BUILD_TYPE=Release \
-DCMAKE_INSTALL_PREFIX=/usr \
-DCMAKE_INSTALL_LIBDIR=lib \
-DLIB_INSTALL_DIR=lib \
-DLIBEXEC_INSTALL_DIR=lib \
-DKDE_INSTALL_USE_QT_SYS_PATHS=ON \
-DSYSCONF_INSTALL_DIR=/etc \
-DBUILD_TESTING=OFF
make
}

package() {
cd build
make DESTDIR="$pkgdir" install
}

I add: -DCMAKE_INSTALL_LIBDIR=lib \ Now it builds and install, but I've not tested it.

@pavbaranov I dont know how to fix that, any help?

This PKGBUILD builds some files in /usr/lib64/ directory:
tar -tf libtmdbqt-git-r21.19c5bd9-1-x86_64.pkg.tar.xz
(...)
usr/lib64/
usr/lib64/cmake/
usr/lib64/libTmdbQt5.so
usr/lib64/libTmdbQt5.so.1.0.0
usr/lib64/libTmdbQt5.so.1.0
usr/lib64/cmake/TmdbQt5/
usr/lib64/cmake/TmdbQt5/TmdbQt5ConfigVersion.cmake
usr/lib64/cmake/TmdbQt5/TmdbQt5Targets-release.cmake
usr/lib64/cmake/TmdbQt5/TmdbQt5Config.cmake
usr/lib64/cmake/TmdbQt5/TmdbQt5Targets.cmake
(...)