add a default heap/general purpose allocator for wasm to base:runtime

base/runtime/internal.odin

@@ -40,6 +40,24 @@ align_forward_int :: #force_inline proc(ptr, align: int) -> int {
 	return p
 }
 
+is_power_of_two_uint :: #force_inline proc "contextless" (x: uint) -> bool {
+	if x <= 0 {
+		return false
+	}
+	return (x & (x-1)) == 0
+}
+
+align_forward_uint :: #force_inline proc(ptr, align: uint) -> uint {
+	assert(is_power_of_two_uint(align))
+
+	p := ptr
+	modulo := p & (align-1)
+	if modulo != 0 {
+		p += align - modulo
+	}
+	return p
+}
+
 is_power_of_two_uintptr :: #force_inline proc "contextless" (x: uintptr) -> bool {
 	if x <= 0 {
 		return false
@@ -58,6 +76,18 @@ align_forward_uintptr :: #force_inline proc(ptr, align: uintptr) -> uintptr {
 	return p
 }
 
+is_power_of_two :: proc {
+	is_power_of_two_int,
+	is_power_of_two_uint,
+	is_power_of_two_uintptr,
+}
+
+align_forward :: proc {
+	align_forward_int,
+	align_forward_uint,
+	align_forward_uintptr,
+}
+
 mem_zero :: proc "contextless" (data: rawptr, len: int) -> rawptr {
 	if data == nil {
 		return nil
@@ -1055,4 +1085,4 @@ __read_bits :: proc "contextless" (dst, src: [^]byte, offset: uintptr, size: uin
 		dst[j>>3] &~=       1<<(j&7)
 		dst[j>>3]  |= the_bit<<(j&7)
 	}
-}
+}