Use pkgconfig for BuildRequires

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

devhelp.spec

@@ -11,19 +11,14 @@ URL: https://wiki.gnome.org/Apps/Devhelp
 #VCS: git:git://git.gnome.org/devhelp
 Source: https://download.gnome.org/sources/devhelp/3.15/%{name}-%{version}.tar.xz
 
-### Dependencies ###
-
-Requires(post):   /usr/bin/gtk-update-icon-cache
-Requires(postun): /usr/bin/gtk-update-icon-cache
-
 ### Build Dependencies ###
 
 BuildRequires: chrpath
 BuildRequires: desktop-file-utils >= 0.3
 BuildRequires: gettext
 BuildRequires: intltool
-BuildRequires: gtk3-devel
-BuildRequires: webkitgtk4-devel
+BuildRequires: pkgconfig(gtk+-3.0)
+BuildRequires: pkgconfig(webkit2gtk-4.0)
 
 %description
 Devhelp is an API documentation browser for the GNOME desktop.
@@ -108,6 +103,7 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor >&/dev/null || :
 - Update to 3.15.90
 - Update URL
 - Use license macro for COPYING
+- Use pkgconfig for BuildRequires
 
 * Mon Sep 22 2014 Kalev Lember <kalevlember@gmail.com> - 1:3.14.0-1
 - Update to 3.14.0