add realloc (and update c_allocator)

examples/programs/mem_allocator/main.bro

@@ -150,6 +150,78 @@ task_list_deinit func(list @mut TaskList) void {
 }
 
 main func() i32 {
+	resized ?*mut u8 = mem.realloc(mem.c_allocator, none, 0, 4, 1)
+	if resized |bytes| {
+		bytes[0] = 10
+		bytes[1] = 20
+		bytes[2] = 30
+		bytes[3] = 40
+	} else {
+		return 20
+	}
+
+	grown ?*mut u8 = mem.realloc(mem.c_allocator, resized, 4, 8, 1)
+	if grown |bytes| {
+		resized = grown
+		if bytes[0] != 10 or bytes[1] != 20 or bytes[2] != 30 or bytes[3] != 40 {
+			mem.free(mem.c_allocator, grown, 8, 1)
+			return 21
+		}
+	} else {
+		mem.free(mem.c_allocator, resized, 4, 1)
+		return 22
+	}
+
+	shrunk ?*mut u8 = mem.realloc(mem.c_allocator, resized, 8, 2, 1)
+	if shrunk |bytes| {
+		resized = shrunk
+		if bytes[0] != 10 or bytes[1] != 20 {
+			mem.free(mem.c_allocator, shrunk, 2, 1)
+			return 23
+		}
+	} else {
+		mem.free(mem.c_allocator, resized, 8, 1)
+		return 24
+	}
+
+	invalid ?*mut u8 = mem.realloc(mem.c_allocator, resized, 2, 4, 24)
+	if invalid |memory| {
+		mem.free(mem.c_allocator, memory, 4, 24)
+		mem.free(mem.c_allocator, resized, 2, 1)
+		return 25
+	}
+	if resized |bytes| {
+		if bytes[0] != 10 or bytes[1] != 20 {
+			mem.free(mem.c_allocator, resized, 2, 1)
+			return 26
+		}
+	}
+
+	resized = mem.realloc(mem.c_allocator, resized, 2, 0, 1)
+	if resized |memory| {
+		mem.free(mem.c_allocator, memory, 0, 1)
+		return 27
+	}
+
+	over_aligned ?*mut u8 = mem.alloc(mem.c_allocator, 4, 32)
+	if over_aligned |bytes| {
+		bytes[0] = 11
+		bytes[1] = 22
+	} else {
+		return 28
+	}
+	over_aligned_grown ?*mut u8 = mem.realloc(mem.c_allocator, over_aligned, 4, 8, 32)
+	if over_aligned_grown |bytes| {
+		if bytes[0] != 11 or bytes[1] != 22 {
+			mem.free(mem.c_allocator, over_aligned_grown, 8, 32)
+			return 29
+		}
+		mem.free(mem.c_allocator, over_aligned_grown, 8, 32)
+	} else {
+		mem.free(mem.c_allocator, over_aligned, 4, 32)
+		return 30
+	}
+
 	zero_alignment ?*mut u8 = mem.alloc(mem.c_allocator, 8, 0)
 	if zero_alignment |memory| {
 		mem.free(mem.c_allocator, memory, 8, 0)