bshell: re-organise build into three separate components

bshell: the front-end binary
bshell.runtime: contains the parser, compiler, and classes needed to run bshell scripts
bshell.core: contains the builtin commandlets and aliases

bshell.runtime/compile/label.c

@@ -0,0 +1,67 @@
+#include "compile-node.h"
+
+size_t compile_declare_label(struct compile_ctx *ctx)
+{
+	size_t id = ctx->c_labels.count;
+	struct compile_label *label = fx_vector_emplace_back(
+		ctx->c_labels,
+		NULL);
+	return id;
+}
+
+void compile_define_label(struct compile_ctx *ctx, size_t label_id)
+{
+	size_t offset = 0;
+	bshell_scriptblock_get_text(ctx->c_block, NULL, &offset);
+	offset *= sizeof(bshell_instruction);
+	ctx->c_labels.items[label_id].l_ip = offset;
+}
+
+void compile_ref_label(struct compile_ctx *ctx, size_t label_id)
+{
+	struct compile_label_ref *ref = malloc(sizeof *ref);
+	if (!ref) {
+		return;
+	}
+
+	memset(ref, 0x0, sizeof *ref);
+	ref->ref_label_id = label_id;
+	bshell_scriptblock_get_text(ctx->c_block, NULL, &ref->ref_offset);
+	ref->ref_offset *= sizeof(bshell_instruction);
+	fx_queue_push_back(&ctx->c_label_refs, &ref->ref_entry);
+}
+
+enum bshell_status compile_resolve_labels(struct compile_ctx *ctx)
+{
+	fx_queue_entry *cur = fx_queue_pop_front(&ctx->c_label_refs);
+	while (cur) {
+		struct compile_label_ref *ref = fx_unbox(
+			struct compile_label_ref,
+			cur,
+			ref_entry);
+		struct compile_label *label = &ctx->c_labels.items
+		                                       [ref->ref_label_id];
+
+		long long rel_value = (long long)label->l_ip
+		                    - (long long)ref->ref_offset;
+
+		enum bshell_opcode op;
+		uint32_t arg;
+		bshell_scriptblock_read_instruction(
+			ctx->c_block,
+			ref->ref_offset,
+			&op,
+			&arg);
+		arg = (uint32_t)rel_value;
+		bshell_scriptblock_patch_instruction(
+			ctx->c_block,
+			ref->ref_offset,
+			op,
+			arg);
+
+		free(ref);
+		cur = fx_queue_pop_front(&ctx->c_label_refs);
+	}
+
+	return BSHELL_SUCCESS;
+}