build: fix sysctl() detection on macOS

sysctl() on *BSD takes a "const int *name", whereas sysctl() on macOS
it takes an "int *name". So our configure check and sysctl() detection on
macOS currently fails:

```bash
/usr/include/sys/sysctl.h:759:9: note: candidate function not viable:
	no known conversion from 'const int [2]' to 'int *' for 1st argument
int     sysctl(int *, u_int, void *, size_t *, void *, size_t);
```

This change removes the name argument from the sysctl() detection check,
meaning we will detect correctly on macOS and *BSD.

For consistency we also switch to using the more generic, non-const
version of the name parameter in the rest of our usage.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/random.cpp b/src/random.cpp
index f7f3dd9de3..2a27e6ba0d 100644
--- a/src/random.cpp
+++ b/src/random.cpp
@@ -321,10 +321,10 @@ void GetOSRand(unsigned char *ent32)
         RandFailure();
     }
 #elif defined(HAVE_SYSCTL_ARND)
-    /* FreeBSD and similar. It is possible for the call to return less
+    /* FreeBSD, NetBSD and similar. It is possible for the call to return less
      * bytes than requested, so need to read in a loop.
      */
-    static const int name[2] = {CTL_KERN, KERN_ARND};
+    static int name[2] = {CTL_KERN, KERN_ARND};
     int have = 0;
     do {
         size_t len = NUM_OS_RANDOM_BYTES - have;