fontconfig: needs host-gperf

Commit 701380c53b4d("fontconfig: add build fix for glibc 2.25") added
a patch that touches src/fcobjs.h. Package build system detects change
in timestamp and tries to regenerate fcobjshash.gperf which requires
gperf tool. So this commit adds dependency on host-gperf.

Since the patch is in upstream fontconfig, we can get rid of this
dependency once version is bumped next time.

Fixes:
  http://autobuild.buildroot.net/results/174/17471088b26ebc840d1922d7f2aa9e69b4b49ced

Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Rahul Bedarkar <rahul.bedarkar@imgtec.com>
[Thomas: improve comment in the code.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/fontconfig/fontconfig.mk

@@ -8,8 +8,12 @@ FONTCONFIG_VERSION = 2.12.1
 FONTCONFIG_SITE = http://fontconfig.org/release
 FONTCONFIG_SOURCE = fontconfig-$(FONTCONFIG_VERSION).tar.bz2
 FONTCONFIG_INSTALL_STAGING = YES
-FONTCONFIG_DEPENDENCIES = freetype expat host-pkgconf
-HOST_FONTCONFIG_DEPENDENCIES = host-freetype host-expat host-pkgconf
+
+# When
+# 0001-Avoid-conflicts-with-integer-width-macros-from-TS-1866.patch is
+# removed, the host-gperf dependency should be removed.
+FONTCONFIG_DEPENDENCIES = freetype expat host-pkgconf host-gperf
+HOST_FONTCONFIG_DEPENDENCIES = host-freetype host-expat host-pkgconf host-gperf
 FONTCONFIG_LICENSE = fontconfig license
 FONTCONFIG_LICENSE_FILES = COPYING