WITH_CCACHE_BUILD + WITH_META_MODE: Ignore ccache changes.

Ccache will not affect the output of the objects, so just ignore it for
meta mode handling.  This avoids having everything rebuild if ccache is
updated.

Sponsored by:	EMC / Isilon Storage Division

share/mk/bsd.compiler.mk

@@ -96,6 +96,9 @@ CCACHE_DIR:=	${CCACHE_DIR:tA}
 .MAKE.META.IGNORE_PATHS+= ${CCACHE_DIR}
 .export CCACHE_DIR
 .endif
+# ccache doesn't affect build output so let it slide for meta mode
+# comparisons.
+.MAKE.META.IGNORE_PATHS+= ${CCACHE_BIN}
 ccache-print-options: .PHONY
 	@${CCACHE_BIN} -p
 .endif	# exists(${CCACHE_BIN})