Use os_posix in gyp file, this patch was tested on Solaris, NetBSD, and OpenBSD.

libjpeg.gyp

Index: libjpeg.gyp
===================================================================
--- libjpeg.gyp	(revision 111873)
+++ libjpeg.gyp	(working copy)
@@ -6,11 +6,13 @@
   'variables': {
     'shared_generated_dir': '<(SHARED_INTERMEDIATE_DIR)/third_party/libjpeg_turbo',
     'conditions': [
-      [ 'chromeos==1 or OS=="freebsd" or OS=="openbsd"', {
+      [ 'chromeos == 1 or (os_posix == 1 and \
+        OS != "mac" and OS != "linux" and OS != "android")', {
         # Link to system .so since we already use it due to GTK.
         # See crbug.com/30288 and 31427 for why we skip OS=="linux" above.
         'use_system_libjpeg%': 1,
-      }, {  # chromeos!=1 and OS!="freebsd" and OS!="openbsd"
+      }, {  # chromeos != 1 and (os_posix != 1 or
+            # OS == "mac" or OS == "linux" or OS == "android")
         'use_system_libjpeg%': 0,
       }],
       [ 'OS=="win"', {