BuildSystem: Cleanup userspace directory layout

userspace programs are now in userspace/programs
userspace tests are now in userspace/tests

This makes listing userspace projects much cleaner. Libraries were
already separated to their own directory, so other programs should also.

userspace/programs/chmod/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(chmod ${SOURCES})
+banan_link_library(chmod libc)
+
+install(TARGETS chmod OPTIONAL)

userspace/programs/chmod/main.cpp

@@ -0,0 +1,43 @@
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+
+void usage(const char* argv0, int ret)
+{
+	FILE* out = (ret == 0) ? stdout : stderr;
+	fprintf(out, "usage: %s MODE FILE...\n", argv0);
+	fprintf(out, "  Change the mode of each FILE to MODE.\n");
+	exit(ret);
+}
+
+int main(int argc, char** argv)
+{
+	if (argc <= 2)
+		usage(argv[0], 1);
+
+	int base = (argv[1][0] == '0') ? 8 : 10;
+
+	mode_t mode = 0;
+	for (const char* ptr = argv[1]; *ptr; ptr++)
+	{
+		if (!isdigit(*ptr))
+		{
+			fprintf(stderr, "Invalid MODE %s\n", argv[1]);
+			usage(argv[0], 1);
+		}
+		mode = (mode * base) + (*ptr - '0');
+	}
+
+	int ret = 0;
+	for (int i = 2; i < argc; i++)
+	{
+		if (chmod(argv[i], mode) == -1)
+		{
+			perror("chmod");
+			ret = 1;
+		}
+	}
+
+	return ret;
+}