diff --git a/configure b/configure
index 704d4a4544..33835d9d1d 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Id: configure.in 14834 2008-04-14 02:06:52Z hdftest .
+# From configure.in Id: configure.in 14851 2008-04-21 00:00:23Z hdftest .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61 for HDF5 1.8.0-snap4.
 #
@@ -43877,6 +43877,18 @@ if test "${enable_threadsafe+set}" = set; then
 fi
 
 
+if test "X${HDF_CXX}" = "Xyes" -a "X${enable_threadsafe}" = "Xyes"; then
+  { { echo "$as_me:$LINENO: error: --enable-cxx and --enable-threadsafe flags are incompatible" >&5
+echo "$as_me: error: --enable-cxx and --enable-threadsafe flags are incompatible" >&2;}
+   { (exit 1); exit 1; }; }
+fi
+
+if test "X${HDF_FORTRAN}" = "Xyes" -a "X${enable_threadsafe}" = "Xyes"; then
+  { { echo "$as_me:$LINENO: error: --enable-fortran and --enable-threadsafe flags are incompatible" >&5
+echo "$as_me: error: --enable-fortran and --enable-threadsafe flags are incompatible" >&2;}
+   { (exit 1); exit 1; }; }
+fi
+
 case "X-$THREADSAFE" in
   X-|X-no)
     { echo "$as_me:$LINENO: result: no" >&5
diff --git a/configure.in b/configure.in
index 5d3f3a6490..24087b60ab 100644
--- a/configure.in
+++ b/configure.in
@@ -1681,6 +1681,17 @@ AC_ARG_ENABLE([threadsafe],
                               [Enable thread safe capability])],
               THREADSAFE=$enableval)
 
+dnl The --enable-threadsafe flag is not compatible with --enable-cxx.
+dnl If the user tried to specify both flags, throw an error.
+if test "X${HDF_CXX}" = "Xyes" -a "X${enable_threadsafe}" = "Xyes"; then
+  AC_MSG_ERROR([--enable-cxx and --enable-threadsafe flags are incompatible])
+fi
+
+dnl --enable-threadsafe is also incompatible with --enable-fortran.
+if test "X${HDF_FORTRAN}" = "Xyes" -a "X${enable_threadsafe}" = "Xyes"; then
+  AC_MSG_ERROR([--enable-fortran and --enable-threadsafe flags are incompatible])
+fi
+
 case "X-$THREADSAFE" in
   X-|X-no)
     AC_MSG_RESULT([no])
diff --git a/src/Makefile.in b/src/Makefile.in
index d4ab94e53e..c3d719385b 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -82,19 +82,20 @@ am_libhdf5_la_OBJECTS = H5.lo H5checksum.lo H5dbg.lo H5system.lo \
 	H5timer.lo H5trace.lo H5A.lo H5Abtree2.lo H5Adense.lo \
 	H5Adeprec.lo H5Aint.lo H5Atest.lo H5AC.lo H5B.lo H5Bcache.lo \
 	H5B2.lo H5B2cache.lo H5B2dbg.lo H5B2int.lo H5B2stat.lo \
-	H5B2test.lo H5C.lo H5CS.lo H5D.lo H5Dchunk.lo H5Dcompact.lo H5Dcontig.lo \
-	H5Ddbg.lo H5Ddeprec.lo H5Defl.lo H5Dfill.lo H5Dint.lo H5Dio.lo \
-	H5Distore.lo H5Dmpio.lo H5Doh.lo H5Dscatgath.lo H5Dselect.lo H5Dtest.lo \
-	H5E.lo H5Edeprec.lo H5Eint.lo H5F.lo H5Fdbg.lo H5Ffake.lo \
-	H5Fmount.lo H5Fsfile.lo H5Fsuper.lo H5Ftest.lo H5FD.lo \
-	H5FDcore.lo H5FDdirect.lo H5FDfamily.lo H5FDlog.lo H5FDmpi.lo \
-	H5FDmpio.lo H5FDmpiposix.lo H5FDmulti.lo H5FDsec2.lo \
-	H5FDspace.lo H5FDstdio.lo H5FL.lo H5FO.lo H5FS.lo H5FScache.lo \
-	H5FSdbg.lo H5FSsection.lo H5G.lo H5Gbtree2.lo H5Gcompact.lo \
-	H5Gdense.lo H5Gdeprec.lo H5Gent.lo H5Gint.lo H5Glink.lo \
-	H5Gloc.lo H5Gname.lo H5Gnode.lo H5Gobj.lo H5Goh.lo H5Gstab.lo \
-	H5Gtest.lo H5Gtraverse.lo H5HF.lo H5HFbtree2.lo H5HFcache.lo \
-	H5HFdbg.lo H5HFdblock.lo H5HFdtable.lo H5HFhdr.lo H5HFhuge.lo \
+	H5B2test.lo H5C.lo H5CS.lo H5D.lo H5Dchunk.lo H5Dcompact.lo \
+	H5Dcontig.lo H5Ddbg.lo H5Ddeprec.lo H5Defl.lo H5Dfill.lo \
+	H5Dint.lo H5Dio.lo H5Distore.lo H5Dmpio.lo H5Doh.lo \
+	H5Dscatgath.lo H5Dselect.lo H5Dtest.lo H5E.lo H5Edeprec.lo \
+	H5Eint.lo H5F.lo H5Fdbg.lo H5Ffake.lo H5Fmount.lo H5Fsfile.lo \
+	H5Fsuper.lo H5Ftest.lo H5FD.lo H5FDcore.lo H5FDdirect.lo \
+	H5FDfamily.lo H5FDlog.lo H5FDmpi.lo H5FDmpio.lo \
+	H5FDmpiposix.lo H5FDmulti.lo H5FDsec2.lo H5FDspace.lo \
+	H5FDstdio.lo H5FL.lo H5FO.lo H5FS.lo H5FScache.lo H5FSdbg.lo \
+	H5FSsection.lo H5G.lo H5Gbtree2.lo H5Gcompact.lo H5Gdense.lo \
+	H5Gdeprec.lo H5Gent.lo H5Gint.lo H5Glink.lo H5Gloc.lo \
+	H5Gname.lo H5Gnode.lo H5Gobj.lo H5Goh.lo H5Gstab.lo H5Gtest.lo \
+	H5Gtraverse.lo H5HF.lo H5HFbtree2.lo H5HFcache.lo H5HFdbg.lo \
+	H5HFdblock.lo H5HFdtable.lo H5HFhdr.lo H5HFhuge.lo \
 	H5HFiblock.lo H5HFiter.lo H5HFman.lo H5HFsection.lo \
 	H5HFspace.lo H5HFstat.lo H5HFtest.lo H5HFtiny.lo H5HG.lo \
 	H5HGdbg.lo H5HL.lo H5HLdbg.lo H5HP.lo H5I.lo H5L.lo \