runtime: improve numcpu detection

std/runtime/mem.jule

@@ -79,4 +79,16 @@ fn sliceAsStr(b: []byte): str {
 		ret ""
 	}
 	ret unsafe { strBytePtr(&b[0], len(b)) }
+}
+
+// Fills the first n bytes of the pointer p with the constant byte b.
+unsafe fn memset(mut p: *unsafe, b: byte, mut n: uint) {
+	if p == nil {
+		ret
+	}
+	mut bp := (*byte)(p)
+	for n > 0; n-- {
+		*bp = b
+		bp++
+	}
 }

std/runtime/sysconf_darwin.jule

@@ -2,8 +2,12 @@
 // Use of this source code is governed by a BSD 3-Clause
 // license that can be found in the LICENSE file.
 
+// See: macOS 10.5 SDK
+// https://github.com/phracker/MacOSX-SDKs/blob/master/MacOSX10.5.sdk/usr/include/unistd.h
+
 use integ "std/jule/integrated"
 
 cpp fn sysconf(name: integ::Int): integ::Long
 
-const _SC_NPROCESSORS_ONLN = 58
+const _SC_NPROCESSORS_CONF = 0x0039
+const _SC_NPROCESSORS_ONLN = 0x003A

std/runtime/sysconf_linux.jule

@@ -2,8 +2,12 @@
 // Use of this source code is governed by a BSD 3-Clause
 // license that can be found in the LICENSE file.
 
+// See: Linux Standard Base Core Specification, Generic Part
+// https://refspecs.linuxbase.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic.html
+
 use integ "std/jule/integrated"
 
 cpp fn sysconf(name: integ::Int): integ::Long
 
-const _SC_NPROCESSORS_ONLN = 84
+const _SC_NPROCESSORS_CONF = 0x0053
+const _SC_NPROCESSORS_ONLN = 0x0054

std/runtime/thread_unix.jule

@@ -68,7 +68,15 @@ fn osyield() {
 // This function must initialize critical data of the typical Jule program.
 fn __init() {
 	// Set numcpu.
-	numcpu = unsafe { int(cpp.sysconf(_SC_NPROCESSORS_ONLN)) }
+	{
+		numcpu = unsafe { int(cpp.sysconf(_SC_NPROCESSORS_ONLN)) }
+		if numcpu == 0 {
+			numcpu = unsafe { int(cpp.sysconf(_SC_NPROCESSORS_CONF)) }
+		}
+		if numcpu == 0 {
+			numcpu = 1
+		}
+	}
 	// Push the main thread to threads.
 	// See the documentation of the pushNewThread function.
 	// The |threads| should be initialized here, because compiler will not do it.

std/runtime/thread_windows.jule

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 use integ "std/jule/integrated"
+use "std/mem"
 use "std/sys"
 
 cpp unsafe fn CreateThread(*unsafe, int, *unsafe, *unsafe, int, *unsafe): *unsafe
@@ -71,8 +72,14 @@ fn __init() {
 	// Set numcpu.
 	{
 		let info: cpp.SYSTEM_INFO
-		unsafe { cpp.GetSystemInfo(&info) }
+		unsafe {
+			memset(&info, 0, mem::SizeOf(cpp.SYSTEM_INFO))
+			cpp.GetSystemInfo(&info)
+		}
 		numcpu = int(info.dwNumberOfProcessors)
+		if numcpu == 0 {
+			numcpu = 1
+		}
 	}
 	// Push the main thread to threads.
 	// See the documentation of the pushNewThread function.