Use pkgconfig for BuildRequires

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

libproxy.spec

@@ -14,22 +14,23 @@ Source0:        https://github.com/libproxy/%{name}/archive/%{version}.tar.gz
 # http://code.google.com/p/libproxy/issues/detail?id=152
 Patch0:         0001-Add-config-module-for-querying-PacRunner-d-mon.patch
 
-BuildRequires:  python-devel
+BuildRequires:  python2-devel
 BuildRequires:  libmodman-devel >= 2.0.1
 BuildRequires:  cmake >= 2.6.0
 
 %if ! 0%{?bootstrap}
+# gnome
+BuildRequires:  pkgconfig(gio-2.0) >= 2.26
 # mozjs
-BuildRequires: pkgconfig(mozjs185)
+BuildRequires:  pkgconfig(mozjs185)
 # NetworkManager
-BuildRequires:  NetworkManager-devel
+BuildRequires:  pkgconfig(NetworkManager)
-BuildRequires:  dbus-devel
+# pacrunner (and NetworkManager)
+BuildRequires:  pkgconfig(dbus-1)
 # webkit (gtk3)
-BuildRequires:  webkitgtk3-devel
+BuildRequires:  pkgconfig(javascriptcoregtk-3.0) >= 1.5.0
 # kde
 BuildRequires:  /usr/bin/kreadconfig5
-# pacrunner
-BuildRequires:  dbus-devel
 %else
 # Obsoletes of disabled subpackages.
 Provides: %{name}-mozjs = %{version}-%{release}
@@ -130,7 +131,6 @@ PacRunner.
 Summary:        Development files for %{name}
 Group:          Development/Libraries
 Requires:       %{name}%{?_isa} = %{version}-%{release}
-Requires:       pkgconfig
 
 %description    devel
 The %{name}-devel package contains libraries and header files for
@@ -215,6 +215,7 @@ make test
 - Simplify conditional macros
 - Use isa macro when requiring base package
 - Use license macro for COPYING
+- Use pkgconfig for BuildRequires
 
 * Thu Feb 04 2016 Fedora Release Engineering <releng@fedoraproject.org> - 0.4.11-13
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_24_Mass_Rebuild