[svn-r20677] Merge packed bits option from 1.8 branch to trunk. CMake only. Autotools merge to come.

Tested: local Linux

tools/testfiles/tpbitsSigned.ddl

@@ -0,0 +1,31 @@
+#############################
+Expected output for 'h5dump -d /DS08BITS -M 0,2,2,6 packedbits.h5'
+#############################
+HDF5 "packedbits.h5" {
+DATASET "/DS08BITS" {
+   DATATYPE  H5T_STD_I8LE
+   DATASPACE  SIMPLE { ( 8, 8 ) / ( 8, 8 ) }
+   PACKED_BITS OFFSET=0 LENGTH=2
+   DATA {
+   (0,0): 3, 2, 0, 0, 0, 0, 0, 0,
+   (1,0): 2, 0, 0, 0, 0, 0, 0, 0,
+   (2,0): 0, 0, 0, 0, 0, 0, 0, 0,
+   (3,0): 0, 0, 0, 0, 0, 0, 0, 0,
+   (4,0): 0, 0, 0, 0, 0, 0, 0, 0,
+   (5,0): 0, 0, 0, 0, 0, 0, 0, 0,
+   (6,0): 0, 0, 0, 0, 0, 0, 0, 0,
+   (7,0): 0, 0, 0, 0, 0, 0, 0, 0
+   }
+   PACKED_BITS OFFSET=2 LENGTH=6
+   DATA {
+   (0,0): 63, 63, 63, 62, 60, 56, 48, 32,
+   (1,0): 63, 63, 62, 60, 56, 48, 32, 0,
+   (2,0): 63, 62, 60, 56, 48, 32, 0, 0,
+   (3,0): 62, 60, 56, 48, 32, 0, 0, 0,
+   (4,0): 60, 56, 48, 32, 0, 0, 0, 0,
+   (5,0): 56, 48, 32, 0, 0, 0, 0, 0,
+   (6,0): 48, 32, 0, 0, 0, 0, 0, 0,
+   (7,0): 32, 0, 0, 0, 0, 0, 0, 0
+   }
+}
+}