strange abuild failed at line 8

APKBUILD

# Contributor: Daniel YC Lin <dlin.tw@gmail.com>
# Maintainer: Daniel YC Lin <dlin.tw@gmail.com>
pkgname=synergy
pkgver=1.8.7
pkgrel=1
pkgdesc='Share a single mouse and keyboard between multiple computers'
url='https://symless.com/synergy/'
arch=('x86' 'x86_64')
license=('GPL2')
depends=('gcc-libs' 'libxtst' 'libxinerama' 'libxkbcommon-x11' 'avahi' 'curl' 'openssl')
makedepends=('libxt' 'cmake' 'qt5-base' 'gmock' 'gtest')
#install=""
subpackages="$pkgname-doc"
source=(synergy-${pkgver}.tar.gz::https://github.com/symless/synergy/archive/v${pkgver}-stable.tar.gz)
builddir="$srcdir/"
#  cd synergy-${pkgver}-stable

build() {
	cd "$builddir"
  msg2 "Building core..."
  (cd build
    cmake -DCMAKE_INSTALL_PREFIX=/usr ..
    # unittests don't pass with optimization (segfault on nullptr)
    sed 's|\-O2|\-O0|g' -i src/test/unittests/CMakeFiles/unittests.dir/{flags.make,link.txt}
    make
  )

  msg2 "Building GUI..."
  (cd src/gui
    qmake
    make
  )
}

package() {
	cd "$builddir"
  cd synergy-${pkgver}-stable

  # install binary
  install -Dm 755 bin/{synergy,synergyc,synergyd,synergys,syntool,usynergy} -t "${pkgdir}/usr/bin"

  # install config
  install -Dm 644 doc/${pkgname}.conf* -t "${pkgdir}/etc"

  # install manfiles
  install -Dm 644 "doc/${pkgname}c.man" "${pkgdir}/usr/share/man/man1/${pkgname}c.1"
  install -Dm 644 "doc/${pkgname}s.man" "${pkgdir}/usr/share/man/man1/${pkgname}s.1"

  # install systemd service and socket
  install -Dm 644 "${srcdir}"/synergys.{service,socket} -t "${pkgdir}/usr/lib/systemd/user"

  # install desktop/icon stuff
  install -Dm 644 "res/synergy.ico" -t "${pkgdir}/usr/share/icons"
  install -Dm 644 "res/synergy.desktop" -t "${pkgdir}/usr/share/applications"
}