Merge pull request #11762 from NixOS/mergify/bp/2.24-maintenance/pr-11750

Fix building on OpenBSD (backport #11750)

mk/libraries.mk

@@ -86,7 +86,9 @@ define build-library
     else
       ifndef HOST_DARWIN
         ifndef HOST_WINDOWS
-          $(1)_LDFLAGS += -Wl,-z,defs
+	  ifndef HOST_OPENBSD
+            $(1)_LDFLAGS += -Wl,-z,defs
+          endif
         endif
       endif
     endif

mk/platform.mk

@@ -21,6 +21,10 @@ ifdef HOST_OS
     HOST_NETBSD = 1
     HOST_UNIX = 1
   endif
+  ifeq ($(patsubst openbsd%,,$(HOST_KERNEL)),)
+    HOST_OPENBSD = 1
+    HOST_UNIX = 1
+  endif
   ifeq ($(HOST_KERNEL), linux)
     HOST_LINUX = 1
     HOST_UNIX = 1

package.nix

@@ -75,7 +75,9 @@
 #
 # Temporarily disabled on Windows because the `GC_throw_bad_alloc`
 # symbol is missing during linking.
-, enableGC ? !stdenv.hostPlatform.isWindows
+#
+# Disabled on OpenBSD because of missing `_data_start` symbol while linking
+, enableGC ? !stdenv.hostPlatform.isWindows && !stdenv.hostPlatform.isOpenBSD
 
 # Whether to enable Markdown rendering in the Nix binary.
 , enableMarkdown ? !stdenv.hostPlatform.isWindows