Use pkgconfig for BuildRequires

https://fedoraproject.org/wiki/Packaging:PkgConfigBuildRequires

gcr.spec

@@ -12,24 +12,22 @@ License:        LGPLv2+
 URL:            https://wiki.gnome.org/Projects/CryptoGlue
 Source0:        https://download.gnome.org/sources/%{name}/3.15/%{name}-%{version}.tar.xz
 
+BuildRequires:  pkgconfig(gio-unix-2.0)
+BuildRequires:  pkgconfig(gobject-introspection-1.0)
+BuildRequires:  pkgconfig(gtk+-3.0)
+BuildRequires:  pkgconfig(p11-kit-1)
+BuildRequires:  chrpath
+BuildRequires:  docbook-style-xsl
+BuildRequires:  libgcrypt-devel
 BuildRequires:  desktop-file-utils
 BuildRequires:  intltool
-BuildRequires:  glib2-devel
-BuildRequires:  gobject-introspection-devel
-BuildRequires:  gtk3-devel
-BuildRequires:  p11-kit-devel
-BuildRequires:  gnupg
-BuildRequires:  libgcrypt-devel
-BuildRequires:  libtasn1-tools
-BuildRequires:  libtasn1-devel
-BuildRequires:  chrpath
-BuildRequires:  vala-devel
 BuildRequires:  vala-tools
-BuildRequires:  libxslt
-BuildRequires:  docbook-style-xsl
 %if 0%{?has_valgrind}
 BuildRequires:  valgrind-devel
 %endif
+BuildRequires:  /usr/bin/gpg
+BuildRequires:  /usr/bin/valac
+BuildRequires:  /usr/bin/xsltproc
 
 Conflicts: gnome-keyring < 3.3.0
 
@@ -143,6 +141,7 @@ fi
 - Update to 3.15.90
 - Update URL
 - Add more documentation and use license macro for COPYING
+- Use pkgconfig for BuildRequires
 
 * Sat Feb 21 2015 Till Maas <opensource@till.name> - 3.14.0-3
 - Rebuilt for Fedora 23 Change