Add build system scaffolding and libc headers

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/libc/time/clock.c b/lib/libc/time/clock.c
new file mode 100644
index 00000000..ec2e6084
--- /dev/null
+++ b/lib/libc/time/clock.c
@@ -0,0 +1,16 @@
+#include <time.h>
+#include <limits.h>
+
+clock_t clock(void)
+{
+	struct timespec ts;
+
+	if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts))
+		return -1;
+
+	if (ts.tv_sec > LONG_MAX / 1000000 ||
+	    ts.tv_nsec / 1000 > LONG_MAX - 1000000 * ts.tv_sec)
+		return -1;
+
+	return ts.tv_sec * 1000000 + ts.tv_nsec / 1000;
+}