support for C++ code generation; importcpp and importobjc pragmas

examples/objciface/gnustepex.nim

@@ -0,0 +1,40 @@
+# horrible example of how to interface with GNUStep ...
+
+{.passL: "-lobjc".}
+{.emit: """
+
+#include <objc/Object.h>
+
+@interface Greeter:Object
+{
+}
+
+- (void)greet:(long)x y:(long)dummy;
+
+@end
+
+#include <stdio.h>
+
+@implementation Greeter
+
+- (void)greet:(long)x y:(long)dummy
+{
+	printf("Hello, World!\n");
+}
+
+@end
+
+#include <stdlib.h>
+""".}
+
+type
+  TId {.importc: "id", header: "<objc/Object.h>", final.} = distinct int
+
+proc newGreeter: TId {.importobjc: "Greeter new", nodecl.}
+proc greet(self: TId, x, y: int) {.importobjc: "greet", nodecl.}
+proc free(self: TId) {.importobjc: "free", nodecl.}
+
+var g = newGreeter()
+g.greet(12, 34)
+g.free()
+