Add public imports

Co-authored-by: Copilot <copilot@github.com>

specs/GENERAL.md

@@ -12,3 +12,4 @@ void main() {
 	puts("Hello, world!");
 }
 ```
+.

specs/IMPORTS.md

@@ -0,0 +1,31 @@
+# Imports
+The import statement allows one module access to the public declarations of another module.
+
+## Syntax
+The import statement uses the following syntax:
+
+```c2
+import module_name;
+```
+
+They can optionally be prefixed by the `public` keyword, in which case the module will
+export everything in the import transitively.
+
+For instance,
+
+```c2
+--- a.c2
+module a;
+import b;
+
+--- b.c2
+module b;
+public import c;
+
+--- c.c2
+module c;
+
+// Some declarations
+```
+
+In this example, both module a and b can access the declarations in module c.

v0/ast.h

@@ -4,11 +4,15 @@
 #ifndef AST_H
 #define AST_H
 
+#include <stdbool.h>
 #include <stddef.h>
 
 typedef struct {
 	/// @brief The name of the module being imported.
 	char* module_name;
+
+	/// @brief Whether the import is public or not.
+	bool is_public;
 } ImportDeclaration;
 
 /**