diff --git a/common.gypi b/common.gypi
index 572a1633..8aeb7be4 100644
--- a/common.gypi
+++ b/common.gypi
@@ -158,7 +158,7 @@
             'cflags': [ '-pthreads' ],
             'ldflags': [ '-pthreads' ],
           }],
-          [ 'OS not in "solaris android zos"', {
+          [ 'OS not in "solaris android"', {
             'cflags': [ '-pthread' ],
             'ldflags': [ '-pthread' ],
           }],
@@ -203,6 +203,10 @@
        # pull in V8's postmortem metadata
        'ldflags': [ '-Wl,-z,allextract' ]
      }],
+     ['OS=="zos"', {
+       'cflags': [ '-qlanglvl=extc99', '-qxplink' ],
+       'ldflags': [ '-qxplink' ],
+     }],
     ],
   },
 }
diff --git a/test/test.gyp b/test/test.gyp
index 30310482..7ac1fa26 100644
--- a/test/test.gyp
+++ b/test/test.gyp
@@ -190,10 +190,6 @@
             '_XOPEN_SOURCE=500',
           ],
         }],
-        [ 'OS == "zos"', {
-          'cflags': [ '-qxplink' ],
-          'ldflags': [ '-qxplink' ],
-        }],
         ['uv_library=="shared_library"', {
           'defines': [ 'USING_UV_SHARED=1' ],
           'conditions': [
@@ -254,10 +250,6 @@
             'runner-unix.h',
           ]
         }],
-        [ 'OS == "zos"', {
-          'cflags': [ '-qxplink' ],
-          'ldflags': [ '-qxplink' ],
-        }],
         ['uv_library=="shared_library"', {
           'defines': [ 'USING_UV_SHARED=1' ],
           'conditions': [