Only look for krb5.h if ssl.h was found. Backport of 1.166.

Fixes bug reported in comment to #728322.

1 files changed, 5 insertions, 4 deletions

diff --git a/setup.py b/setup.py
index c1eb84840d..3210a690df 100644
--- a/setup.py
+++ b/setup.py
@@ -372,10 +372,11 @@ class PyBuildExt(build_ext):
                                       '/usr/contrib/ssl/lib/'
                                      ] )
 
-        krb5_h = find_file('krb5.h', inc_dirs,
-                           ['/usr/kerberos/include'])
-        if krb5_h:
-            ssl_incs += krb5_h
+        if ssl_incs is not None:
+            krb5_h = find_file('krb5.h', inc_dirs,
+                               ['/usr/kerberos/include'])
+            if krb5_h:
+                ssl_incs += krb5_h
 
         if ssl_incs is not None and ssl_libs is not None:
             rtlibs = None