Initial project import

tools/v/vlib/builtin/builtin_d_vgc.c.v

@@ -0,0 +1,10 @@
+// builtin_d_vgc.c.v - V Garbage Collector additional support
+// Conditionally compiled when -d vgc is used.
+// The gc_heap_usage/gc_memory_use functions are in allocation.c.v with $if vgc ? branches.
+
+module builtin
+
+// This file exists to ensure the vgc compile define activates VGC-specific code paths
+// throughout the builtin module. The actual VGC implementation is in:
+//   - vgc_d_vgc.c.v: Core types, heap, allocation
+//   - vgc_gc_d_vgc.c.v: GC mark, sweep, orchestration