Also consider libpthread when testing for functions. Removed test for floor().

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11681 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/configure.in b/configure.in
index 8899620..b126204 100644
--- a/configure.in
+++ b/configure.in
@@ -1602,13 +1602,13 @@
 AC_FUNC_MMAP
 AC_TYPE_SIGNAL
 
+AC_CHECK_LIB([pthread], [pthread_create])
 AC_CHECK_LIB([rt], [clock_gettime])
 
 AC_CHECK_FUNCS([     \
         clock_gettime\
         epoll_create \
         epoll_pwait  \
-        floor        \
         klogctl      \
         mallinfo     \
         memchr       \