- Implement NEON runtime detection on FreeBSD 11.* armv6

--- src/arm/cpu.c.orig	2019-05-11 15:23:10 UTC
+++ src/arm/cpu.c
@@ -75,6 +75,36 @@ static unsigned parse_proc_cpuinfo(const char *flag) {
 }
 #endif
 
+#if defined(__FreeBSD__) && __FreeBSD__ < 12
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <elf.h>
+#include <errno.h>
+#include <unistd.h>
+
+#define HAVE_GETAUXVAL
+#define NEON_HWCAP HWCAP_NEON
+static unsigned long getauxval(unsigned long type) {
+  Elf_Auxinfo auxv[AT_COUNT];
+  size_t len = sizeof(auxv);
+  int mib[] = {
+    CTL_KERN,
+    KERN_PROC,
+    KERN_PROC_AUXV,
+    getpid(),
+  };
+
+  if (sysctl(mib, nitems(mib), auxv, &len, NULL, 0) != -1) {
+    for (size_t i = 0; i < nitems(auxv); i++)
+      if ((unsigned long)auxv[i].a_type == type)
+        return auxv[i].a_un.a_val;
+
+    errno = ENOENT;
+  }
+  return 0;
+}
+#endif
+
 COLD unsigned dav1d_get_cpu_flags_arm(void) {
     unsigned flags = 0;
 #if ARCH_AARCH64