diff --git a/README.md b/README.md
index 876491f..5c4238f 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,12 @@ for all the actors to terminate and clean up all the resources used.
 
 
 
+### Valgrind
+
+To make the library aware of being run with helgrind, the program needs to be
+built with `-d:usesValgrind`, otherwise false positives could be reported.
+
+
 ### More to come
 
 Sure.
diff --git a/actors/pool.nim b/actors/pool.nim
index f072af4..0415758 100644
--- a/actors/pool.nim
+++ b/actors/pool.nim
@@ -6,8 +6,6 @@ import isisolated
 import mallinfo
 import valgrind
 
-{.emit:"#include <valgrind/helgrind.h>".}
-
 type
 
   Pool* = object
diff --git a/actors/valgrind.nim b/actors/valgrind.nim
index 565df1d..6a9b3c6 100644
--- a/actors/valgrind.nim
+++ b/actors/valgrind.nim
@@ -1,20 +1,26 @@
 
-{.emit:"#include <valgrind/helgrind.h>".}
+const
+  usesValgrind {.booldefine.} = false
 
-template valgrind_annotate_happens_before*(x) =
-  block:
-    let y {.exportc,inject.} = x
-    {.emit:"ANNOTATE_HAPPENS_BEFORE(y);".}
+when usesValgrind:
+  const header = "<valgrind/helgrind.h>"
 
-template valgrind_annotate_happens_after*(x) =
-  block:
-    let y {.exportc,inject.} = x
-    {.emit:"ANNOTATE_HAPPENS_AFTER(y);".}
+  proc valgrind_annotate_happens_before*(x: pointer) {.
+    header: header, importc: "ANNOTATE_HAPPENS_BEFORE".}
+  proc valgrind_annotate_happens_after*(x: pointer) {.
+    header: header, importc: "ANNOTATE_HAPPENS_AFTER".}
+  proc valgrind_annotate_happens_before_forget_all*(x: pointer) {.
+    header: header, importc: "ANNOTATE_HAPPENS_BEFORE_FORGET_ALL".}
 
-template valgrind_annotate_happens_before_forget_all*(x) =
-  block:
-    let y {.exportc,inject.} = x
-    {.emit:"ANNOTATE_HAPPENS_BEFORE_FORGET_ALL(y);".}
+  let enabled {.header: header, importc: "RUNNING_ON_VALGRIND".}: bool
 
-proc running_on_valgrind*(): bool =
-  {.emit: "result = RUNNING_ON_VALGRIND;".}
+  proc running_on_valgrind*(): bool =
+    {.cast(noSideEffect), cast(gcSafe).}:
+      result = enabled
+
+else:
+  proc valgrind_annotate_happens_before*(x: pointer) = discard
+  proc valgrind_annotate_happens_after*(x: pointer) = discard
+  proc valgrind_annotate_happens_before_forget_all*(x: pointer) = discard
+
+  template running_on_valgrind*(): bool = false
diff --git a/tests/nim.cfg b/tests/nim.cfg
new file mode 100644
index 0000000..fdc9b27
--- /dev/null
+++ b/tests/nim.cfg
@@ -0,0 +1 @@
+--define:usesValgrind
\ No newline at end of file