Fix a stray 'dnl' that my editor line-wrapped into this comment. Thanks
to filcab on IRC for spotting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171573 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index c0af01a..102147c 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -1251,8 +1251,8 @@
                AC_MSG_WARN([dlopen() not found - disabling plugin support]))
 
 dnl Search for the clock_gettime() function. Note that we rely on the POSIX
-dnl macros to detect whether clock_gettime is available, dnl this just finds
-dnl the right libraries to link with.
+dnl macros to detect whether clock_gettime is available, this just finds the
+dnl right libraries to link with.
 AC_SEARCH_LIBS(clock_gettime,rt)
 
 dnl libffi is optional; used to call external functions from the interpreter