phosh/calls: explicitly generate src/config.h

Workaround for #383.

phosh/calls/APKBUILD

@@ -2,7 +2,7 @@
 # Maintainer: Bart Ribbers <bribbers@disroot.org>
 pkgname=calls
 pkgver=0.1.0
-pkgrel=0
+pkgrel=1
 pkgdesc="A phone dialer and call handler"
 arch="all !armhf"
 url="https://gitlab.gnome.org/Community/Purism/calls"
@@ -15,6 +15,7 @@ builddir="$srcdir/$pkgname-v$pkgver"
 
 build() {
 	meson . _build --prefix=/usr
+	ninja -C _build src/config.h # workaround for #383
 	ninja -C _build
 }