record the C++ compiler version in the VM, and expose it with a vm-compiler word

core/alien/strings/strings.factor

@@ -66,6 +66,7 @@ M: string string>symbol string>symbol* ;
 M: sequence string>symbol [ string>symbol* ] map ;
 
 [
-    8 special-object utf8 alien>string string>cpu \ cpu set-global
-    9 special-object utf8 alien>string string>os \ os set-global
+     8 special-object utf8 alien>string string>cpu \ cpu set-global
+     9 special-object utf8 alien>string string>os \ os set-global
+    67 special-object utf8 alien>string \ vm-compiler set-global
 ] "alien.strings" add-startup-hook

core/system/system.factor

@@ -24,6 +24,8 @@ UNION: unix bsd solaris linux haiku ;
 
 : os ( -- class ) \ os get-global ; foldable
 
+: vm-compiler ( -- string ) \ vm-compiler get-global ; foldable
+
 <PRIVATE
 
 : string>cpu ( str -- class )

vm/factor.cpp

@@ -136,6 +136,7 @@ void factor_vm::init_factor(vm_parameters *p)
 	special_objects[OBJ_EXECUTABLE] = allot_alien(false_object,(cell)p->executable_path);
 	special_objects[OBJ_ARGS] = false_object;
 	special_objects[OBJ_EMBEDDED] = false_object;
+	special_objects[OBJ_VM_COMPILER] = allot_alien(false_object,(cell)FACTOR_COMPILER_VERSION);
 
 	/* We can GC now */
 	gc_off = false;

vm/master.hpp

@@ -29,6 +29,19 @@
 #include <vector>
 #include <iostream>
 
+/* Record compiler version */
+#if defined(__clang__)
+	#define FACTOR_COMPILER_VERSION "Clang (GCC " __VERSION__ ")"
+#elif defined(__INTEL_COMPILER)
+	#define FACTOR_COMPILER_VERSION "Intel C Compiler " #__INTEL_COMPILER
+#elif defined(__GNUC__)
+	#define FACTOR_COMPILER_VERSION "GCC " __VERSION__
+#elif defined(_MSC_FULL_VER)
+	#define FACTOR_COMPILER_VERSION "Microsoft Visual C++ " #_MSC_FULL_VER
+#else
+	#define FACTOR_COMPILER_VERSION "unknown"
+#endif
+
 /* Detect target CPU type */
 #if defined(__arm__)
 	#define FACTOR_ARM

vm/objects.hpp

@@ -95,6 +95,8 @@ enum special_object {
 	OBJ_THREADS = 64,
 	OBJ_RUN_QUEUE = 65,
 	OBJ_SLEEP_QUEUE = 66,
+
+	OBJ_VM_COMPILER = 67,    /* version string of the compiler we were built with */
 };
 
 /* save-image-and-exit discards special objects that are filled in on startup