Implemented const keyword

lib/mem/alloc_linux.q

@@ -1,7 +1,17 @@
 import sys
 
+const prot {
+	read  0x1
+	write 0x2
+}
+
+const map {
+	private   0x02
+	anonymous 0x20
+}
+
 alloc(length Int) -> []Int8 {
-	x := sys.mmap(0, length+8, 0x1|0x2, 0x02|0x20)
+	x := sys.mmap(0, length+8, prot.read|prot.write, map.private|map.anonymous)
 
 	if x < 0x1000 {
 		return x

lib/mem/alloc_mac.q

@@ -1,7 +1,17 @@
 import sys
 
+const prot {
+	read  0x1
+	write 0x2
+}
+
+const map {
+	private   0x02
+	anonymous 0x1000
+}
+
 alloc(length Int) -> []Int8 {
-	x := sys.mmap(0, length+8, 0x1|0x2, 0x02|0x1000)
+	x := sys.mmap(0, length+8, prot.read|prot.write, map.private|map.anonymous)
 
 	if x < 0x1000 {
 		return x

lib/mem/alloc_windows.q

@@ -1,7 +1,16 @@
 import sys
 
+const page {
+	readwrite 0x0004
+}
+
+const mem {
+	commit  0x1000
+	reserve 0x2000
+}
+
 alloc(length Int) -> []Int8 {
-	x := sys.mmap(0, length+8, 0x0004, 0x3000)
+	x := sys.mmap(0, length+8, page.readwrite, mem.commit|mem.reserve)
 
 	if x < 0x1000 {
 		return x