Add fontconfig depends to fix build

Author: tronical

recipes-example/slint-hello-rust/slint-hello-world-rust_git.bb

@@ -7,6 +7,8 @@ HOMEPAGE = "https://github.com/slint-ui/slint"
 LICENSE = "GPL-3.0-only | Slint-Commercial"
 LIC_FILES_CHKSUM = "file://LICENSE;md5=9e911597e678943cde54111f7518e299"
 
+DEPENDS:append = " fontconfig"
+
 S = "${WORKDIR}/git"
 PV = "slint-hello-world-rust-${SRCPV}"