diff -ur ilmbase-2.1.0-orig/IlmThread/Makefile.am ilmbase-2.1.0/IlmThread/Makefile.am
--- ilmbase-2.1.0/IlmThread/Makefile.am	2013-06-18 21:51:38.000000000 +0200
+++ ilmbase-2.1.0/IlmThread/Makefile.am	2014-01-27 17:00:54.326921077 +0100
@@ -14,7 +14,7 @@
 if LIB_SUFFIX_EXISTS
 libIlmThread_la_LDFLAGS += -release @LIB_SUFFIX@
 endif
-libIlmThread_la_LIBADD = ../Iex/libIex.la
+libIlmThread_la_LIBADD = ../Iex/libIex.la -lpthread
 
 libIlmThreadincludedir = $(includedir)/OpenEXR