Fix deps and race conditions in nacl_demos Makefile
Fix deps and race conditions in nacl_demos Makefile


Former-commit-id: 236ae79849ee9a22504f6f69558a669b879e9deb
darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide