harfbuzz-icu detections based on the following upstream commits

- 5f3ae29ffb29c499c1825578ba7f3ffcbf1aa8b9
- ad2a23ec44b692bde43a13b658990770caa8dfc5
- 22b4786377142424bfb6562ff029997acd0846d1

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

Index: webkit-1.11.5/configure.ac
===================================================================
--- webkit-1.11.5.orig/configure.ac
+++ webkit-1.11.5/configure.ac
@@ -938,6 +938,15 @@ PKG_CHECK_MODULES([FREETYPE],
                   freetype2 >= $FREETYPE2_REQUIRED_VERSION
                   harfbuzz])
 fi
+# HarfBuzz 0.9.18 splits harbuzz-icu into a separate library.
+# Since we support earlier HarfBuzz versions we keep this conditional for now.
+m4_define([harfbuzz_required_version], [0.9.7])
+if $PKG_CONFIG --atleast-version 0.9.18 harfbuzz; then
+	PKG_CHECK_MODULES([HARFBUZZ_ICU], [harfbuzz-icu >= $harfbuzz_required_version])
+	FREETYPE_CFLAGS+=" $HARFBUZZ_ICU_CFLAGS"
+	FREETYPE_LIBS+=" $HARFBUZZ_ICU_LIBS"
+fi
+
 AC_SUBST([FREETYPE_CFLAGS])
 AC_SUBST([FREETYPE_LIBS])