Only use libportal for Flatpak builds

There's no need to pull this dependency if Eog is not consumed as
a Flatpak.

eog.spec

@@ -7,7 +7,7 @@
 
 Name:    eog
 Version: 3.38.1
-Release: 1%{?dist}
+Release: 2%{?dist}
 Summary: Eye of GNOME image viewer
 
 # The GFDL has an "or later version" clause embedded inside the license.
@@ -27,7 +27,9 @@ BuildRequires: pkgconfig(lcms2)
 BuildRequires: pkgconfig(libexif) >= %{libexif_version}
 BuildRequires: pkgconfig(libpeas-1.0) >= 0.7.4
 BuildRequires: pkgconfig(libpeas-gtk-1.0) >= 0.7.4
+%if 0%{?flatpak}
 BuildRequires: pkgconfig(libportal)
+%endif
 BuildRequires: pkgconfig(librsvg-2.0)
 BuildRequires: pkgconfig(shared-mime-info)
 BuildRequires: pkgconfig(x11)
@@ -74,7 +76,10 @@ the functionality of the installed %{name} package.
 %setup -q
 
 %build
-%meson -Dgtk_doc=true -Dinstalled_tests=true
+%meson -Dgtk_doc=true -Dinstalled_tests=true \
+    %if ! 0%{?flatpak}
+       -Dlibportal=false
+    %endif
 %meson_build
 
 %install
@@ -110,6 +115,9 @@ desktop-file-validate %{buildroot}/%{_datadir}/applications/org.gnome.eog.deskto
 %{_datadir}/installed-tests/
 
 %changelog
+* Tue Dec 01 2020 Felipe Borges <feborges@redhat.com> - 3.38.1-2
+- Only require libportal for Flatpak builds
+
 * Wed Nov 25 2020 Kalev Lember <klember@redhat.com> - 3.38.1-1
 - Update to 3.38.1