QNX: Fix physical memory detection

On QNX 7.1, this was returning an uninitialized value due to failing
sysctl. Use the accumulated size of all "ram" areas from the asinfo
array in the syspage instead. Also fixes build on QNX 8.0.

Signed-off-by: Matthias von Faber <[email protected]>

os/os-qnx.h

@@ -9,7 +9,7 @@
 #include <sys/statvfs.h>
 #include <sys/ioctl.h>
 #include <sys/utsname.h>
-#include <sys/sysctl.h>
+#include <sys/syspage.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/dcmd_cam.h>
@@ -71,11 +71,17 @@ static inline int blockdev_invalidate_cache(struct fio_file *f)
 
 static inline unsigned long long os_phys_mem(void)
 {
-	int mib[2] = { CTL_HW, HW_PHYSMEM64 };
-	uint64_t mem;
-	size_t len = sizeof(mem);
+	uint64_t mem = 0;
+	const char *const strings = SYSPAGE_ENTRY(strings)->data;
+	const struct asinfo_entry *const begin = SYSPAGE_ENTRY(asinfo);
+	const struct asinfo_entry *const end = begin + SYSPAGE_ENTRY_SIZE(asinfo) / SYSPAGE_ELEMENT_SIZE(asinfo);
 
-	sysctl(mib, 2, &mem, &len, NULL, 0);
+	assert(SYSPAGE_ELEMENT_SIZE(asinfo) == sizeof(struct asinfo_entry));
+
+	for (const struct asinfo_entry *e = begin; e < end; ++e) {
+		if (!strcmp(strings + e->name, "ram"))
+			mem += e->end - e->start + 1;
+	}
 	return mem;
 }