Use ldconfig rpm macro.

fontconfig.spec

@@ -5,7 +5,7 @@
 Summary:	Font configuration and customization library
 Name:		fontconfig
 Version:	2.13.0
-Release:	6%{?dist}
+Release:	7%{?dist}
 # src/ftglue.[ch] is in Public Domain
 # src/fccache.c contains Public Domain code
 # fc-case/CaseFolding.txt is in the UCD
@@ -33,7 +33,8 @@ BuildRequires:	gperf
 
 Requires:	fontpackages-filesystem freetype
 Requires(pre):	freetype >= 2.9.1
-Requires(post):	grep coreutils
+Requires(post):	grep coreutils /sbin/ldconfig
+Requires(postun):	/sbin/ldconfig
 Requires:	font(:lang=en)
 Suggests:	dejavu-sans-fonts
 
@@ -106,7 +107,7 @@ cat %{name}-conf.lang >> %{name}.lang
 make check
 
 %post
-/sbin/ldconfig
+%{?ldconfig: %ldconfig}
 
 umask 0022
 
@@ -122,7 +123,7 @@ if [ -x /usr/bin/fc-cache ] && /usr/bin/fc-cache --version 2>&1 | grep -q %{vers
   HOME=/root /usr/bin/fc-cache -f
 fi
 
-%postun -p /sbin/ldconfig
+%ldconfig_postun
 
 %transfiletriggerin -- /usr/share/fonts /usr/share/X11/fonts/Type1 /usr/share/X11/fonts/TTF /usr/local/share/fonts
 HOME=/root /usr/bin/fc-cache -s
@@ -167,6 +168,9 @@ HOME=/root /usr/bin/fc-cache -s
 %doc fontconfig-devel.txt fontconfig-devel
 
 %changelog
+* Fri Jun 29 2018 Akira TAGOH <tagoh@redhat.com> - 2.13.0-7
+- Use ldconfig rpm macro.
+
 * Thu Jun 07 2018 Akira TAGOH <tagoh@redhat.com> - 2.13.0-6
 - Add Suggests: dejavu-sans-fonts to address pulling the unpredicted
   font package as dependency. (#1321551)