added libpthread_LIBS to fix build in tools
diff --git a/configure.ac b/configure.ac
index 6948d18..8cbe7a7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -98,6 +98,10 @@
 esac
 AM_CONDITIONAL(WIN32, test x$win32 = xtrue)
 
+if test "x$win32" != "xtrue"; then
+  AC_CHECK_LIB(pthread, [pthread_create, pthread_mutex_lock], [AC_SUBST(libpthread_LIBS,[-lpthread])], [AC_MSG_ERROR([libpthread is required to build libusbmuxd])])
+fi
+
 AS_COMPILER_FLAGS(GLOBAL_CFLAGS, "-Wall -Wextra -Wmissing-declarations -Wredundant-decls -Wshadow -Wpointer-arith  -Wwrite-strings -Wswitch-default -Wno-unused-parameter")
 AC_SUBST(GLOBAL_CFLAGS)
 
diff --git a/src/Makefile.am b/src/Makefile.am
index bf9198f..6c21d2c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,7 @@
 AM_CPPFLAGS = -I$(top_srcdir)/include
 
 AM_CFLAGS = $(GLOBAL_CFLAGS) $(libplist_CFLAGS)
-AM_LDFLAGS = $(GLOBAL_LIBS) $(libplist_LIBS)
+AM_LDFLAGS = $(GLOBAL_LIBS) $(libpthread_LIBS) $(libplist_LIBS)
 
 lib_LTLIBRARIES = libusbmuxd.la
 libusbmuxd_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(LIBUSBMUXD_SO_VERSION) -no-undefined
diff --git a/tools/Makefile.am b/tools/Makefile.am
index f1fa2f6..d194501 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -1,5 +1,5 @@
 AM_CFLAGS = $(GLOBAL_CFLAGS) -I$(top_srcdir)/src
-AM_LDFLAGS =
+AM_LDFLAGS = $(libpthread_LIBS)
 
 bin_PROGRAMS = iproxy