sysconf: move in from cpp-cheat

arm baremetal: give more TTBR rationale

userland/linux/sysconf.c

@@ -0,0 +1,13 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#sysconf */
+
+#define _XOPEN_SOURCE 700
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int main(void) {
+    /* Number of processors, not considering affinity:
+     * http://stackoverflow.com/questions/2693948/how-do-i-retrieve-the-number-of-processors-on-c-linux */
+    printf("_SC_NPROCESSORS_ONLN = %ld\n", sysconf(_SC_NPROCESSORS_ONLN));
+    return EXIT_SUCCESS;
+}