Install uthash.h when building ParallelIO using CMake

This commit fixes ESMCI#1551 in the CMake build system (ESMCI#1552 did the same
for autoconf).

Note that relative paths specified in install(FILES ...) are
interpreted as relative to the current source directory, so
${CMAKE_CURRENT_SOURCE_DIR} is not needed.

src/clib/CMakeLists.txt

@@ -49,8 +49,8 @@ endif()
 # Library
 install (TARGETS pioc DESTINATION lib)
 
-# Include/Header File
-install (FILES ${CMAKE_CURRENT_SOURCE_DIR}/pio.h DESTINATION include)
+# Include/Header Files
+install (FILES pio.h uthash.h DESTINATION include)
 
 #==============================================================================
 #  DEFINE THE DEPENDENCIES