build improvements medley

increase RAM used for various build mk files and avoid exceeding MAX_ARG_STRLEN

Do not repeat output path for each entry after cding there first when generating command-line strings.
tested and reduced my build time by 15 seconds or 2.6% from clobber. need to test with ccache -C -c

Change-Id: Ib24ae0fd9c1513bf8b3454f3ebdbeaf2c34ea772