Remove include path to /usr/include.
Fixes bitbake warning:
| WARNING: unclutter-1.09-r0 do_package_qa: QA Issue: unclutter: The compile log indicates that host include and/or library paths were used.
|          Please check the log '/mnt/sdc2/oe-disk/oe-core_master/build/out-glibc/work/armv7at2hf-neon-angstrom-linux-gnueabi/unclutter/1.09-r0/temp/log.do_compile' for more information. [compile-host-path]

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
diff -Naur unclutter-1.09.orig/Makefile unclutter-1.09/Makefile
--- unclutter-1.09.orig/Makefile	2016-07-30 16:43:56.730859141 +0200
+++ unclutter-1.09/Makefile	2016-07-30 16:49:19.603890691 +0200
@@ -10,7 +10,7 @@
            MFLAGS = -$(MAKEFLAGS)
      INSTPGMFLAGS = -c -s
      INSTMANFLAGS = -c
-     TOP_INCLUDES = -I$(INCROOT)
+     TOP_INCLUDES =
       CDEBUGFLAGS = -O
       ALLINCLUDES = $(STD_INCLUDES) $(TOP_INCLUDES) $(INCLUDES) $(EXTRA_INCLUDES)
        ALLDEFINES = $(ALLINCLUDES) $(STD_DEFINES) $(PROTO_DEFINES) $(DEFINES) $(COMPATFLAGS)
@@ -21,7 +21,6 @@
          IRULESRC = $(CONFIGDIR)
         IMAKE_CMD = $(IMAKE) -DUseInstalled -I$(IRULESRC) $(IMAKE_DEFINES)
            BINDIR = $(DESTDIR)/usr/bin/X11
-          INCROOT = $(DESTDIR)/usr/include
           MANPATH = $(DESTDIR)/usr/catman/x11_man
     MANSOURCEPATH = $(MANPATH)/man
            MANDIR = $(MANSOURCEPATH)1