qemu: fix pkg-config usage

This is fixed in latest Gentoo ebuilds already.

BUG=chromium:985180
TEST=CQ passes

Change-Id: Iaed657ef3de4980f4b755dba609324e3ec14ac88
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2213917
Reviewed-by: Alex Klein <saklein@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/app-emulation/qemu/qemu-3.0.0.ebuild b/app-emulation/qemu/qemu-3.0.0.ebuild
index b1cf129..f50fbdf 100644
--- a/app-emulation/qemu/qemu-3.0.0.ebuild
+++ b/app-emulation/qemu/qemu-3.0.0.ebuild
@@ -375,7 +375,7 @@
 	default
 
 	# Fix ld and objcopy being called directly
-	tc-export AR LD OBJCOPY
+	tc-export AR LD OBJCOPY PKG_CONFIG
 
 	# Verbose builds
 	MAKEOPTS+=" V=1"