harfbuzz: remove stale pkg.m4

harfbuzz shipped an old pkg.m4 which overruled the pkg.m4 from the sysroot.
This is now fixed upstream, but until another release is made delete it from the
source tree.

(From OE-Core rev: 44d826327e9336d7490745d5721d79809556b177)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-graphics/harfbuzz/harfbuzz_1.8.8.bb

@@ -27,6 +27,12 @@ EXTRA_OECONF = " \
     --without-graphite2 \
 "
 
+do_configure_prepend() {
+    # This is ancient and can get used instead of the patched one we ship,
+    # so delete it. In 1.8.9 this should be removed upstream.
+    rm -f ${S}/m4/pkg.m4
+}
+
 PACKAGES =+ "${PN}-icu ${PN}-icu-dev"
 
 LEAD_SONAME = "libharfbuzz.so"