diff --git a/lib/posix/posix.nim b/lib/posix/posix.nim
index e206447cc..cdca826ca 100644
--- a/lib/posix/posix.nim
+++ b/lib/posix/posix.nim
@@ -846,7 +846,7 @@ var
   FE_UPWARD* {.importc, header: "<fenv.h>".}: cint
   FE_DFL_ENV* {.importc, header: "<fenv.h>".}: cint
 
-when not defined(haiku):
+when not defined(haiku) and not defined(OpenBSD):
   var
     MM_HARD* {.importc, header: "<fmtmsg.h>".}: cint
       ## Source of the condition is hardware.
@@ -1816,7 +1816,7 @@ proc feholdexcept*(a1: ptr Tfenv): cint {.importc, header: "<fenv.h>".}
 proc fesetenv*(a1: ptr Tfenv): cint {.importc, header: "<fenv.h>".}
 proc feupdateenv*(a1: ptr Tfenv): cint {.importc, header: "<fenv.h>".}
 
-when not defined(haiku):
+when not defined(haiku) and not defined(OpenBSD):
   proc fmtmsg*(a1: int, a2: cstring, a3: cint,
               a4, a5, a6: cstring): cint {.importc, header: "<fmtmsg.h>".}