libostree: override path to gpg-error-config

libostree has begun to use `gpg-error-config` in their configuration
script.
Point out gpg-error-config in staging dir to avoid using the one
installed on the host system.

Fixes:
 http://autobuild.buildroot.net/results/447b96e449e881cf1bd9644cda0f386aa4c75724

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/libostree/Config.in

@@ -1,15 +1,16 @@
 config BR2_PACKAGE_LIBOSTREE
 	bool "libostree"
-	depends on BR2_PACKAGE_LIBGPG_ERROR_ARCH_SUPPORTS # libgpgme
+	depends on BR2_PACKAGE_LIBGPG_ERROR_ARCH_SUPPORTS # libgpgme, libgpg-error
 	depends on !BR2_STATIC_LIBS # libfuse
 	depends on BR2_TOOLCHAIN_HAS_THREADS # libglib2
 	depends on BR2_USE_WCHAR # libglib2
-	depends on BR2_USE_MMU # e2fsprogs, libfuse,libglib2, libgpgme
+	depends on BR2_USE_MMU # e2fsprogs, libfuse, libglib2, libgpgme
 	# doesn't build with musl due to lack of TEMP_FAILURE_RETRY()
 	depends on !BR2_TOOLCHAIN_USES_MUSL
 	select BR2_PACKAGE_E2FSPROGS
 	select BR2_PACKAGE_LIBFUSE
 	select BR2_PACKAGE_LIBGLIB2
+	select BR2_PACKAGE_LIBGPG_ERROR
 	select BR2_PACKAGE_LIBGPGME
 	select BR2_PACKAGE_XZ
 	help

package/libostree/libostree.mk

@@ -10,9 +10,11 @@ LIBOSTREE_SITE = https://github.com/ostreedev/ostree/releases/download/v$(LIBOST
 
 LIBOSTREE_LICENSE = LGPL-2.0+
 LIBOSTREE_LICENSE_FILES = COPYING
-LIBOSTREE_DEPENDENCIES = e2fsprogs host-bison host-pkgconf libfuse libglib2 libgpgme xz
+LIBOSTREE_DEPENDENCIES = e2fsprogs host-bison host-pkgconf libfuse libglib2 libgpg-error libgpgme xz
 LIBOSTREE_INSTALL_STAGING = YES
 
+LIBOSTREE_CONF_ENV = \
+	GPG_ERROR_CONFIG=$(STAGING_DIR)/usr/bin/gpg-error-config
 LIBOSTREE_CONF_OPTS += \
 	--with-gpgme-prefix=$(STAGING_DIR)/usr \
 	--disable-gtk-doc \