Setting SKIP_SELINUX skips searching for selinux.  The current ebuild calls
make 3 times.  The first 2 times we don't need to search for selinux packages
because we might end up not needing them and we get useless warnings.

--- a/Makefile.flags
+++ b/Makefile.flags
@@ -176,12 +176,14 @@
 LDLIBS += pam pam_misc
 endif
 
+ifneq ($(SKIP_SELINUX),y)
 ifeq ($(CONFIG_SELINUX),y)
 SELINUX_PC_MODULES = libselinux libsepol
 $(eval $(call pkg_check_modules,SELINUX,$(SELINUX_PC_MODULES)))
 CPPFLAGS += $(SELINUX_CFLAGS)
 LDLIBS += $(if $(SELINUX_LIBS),$(SELINUX_LIBS:-l%=%),$(SELINUX_PC_MODULES:lib%=%))
 endif
+endif
 
 ifeq ($(CONFIG_FEATURE_NSLOOKUP_BIG),y)
 ifneq (,$(findstring linux,$(shell $(CC) $(CFLAGS) -dumpmachine)))