Fix typo: ptread --> pthread
Closes SF bug #554644.
diff --git a/README b/README
index d69a22c..83cdf3c 100644
--- a/README
+++ b/README
@@ -288,7 +288,7 @@
place. See Misc/AIX-NOTES for some notes on how it's done.
(The optimizer bug reported at this place in previous releases
has been worked around by a minimal code change.) If you get
- errors about ptread_* functions, during compile or during
+ errors about pthread_* functions, during compile or during
testing, try setting CC to a thread-safe (reentrant) compiler,
like "cc_r". For full C++ module support, set CC="xlC_r" (or
CC="xlC" without thread support).