include: Moved kdb.h.in, updated CMakeLists

kdb.h.in moved into subfolder elektra, so that kdb.h can be included by <elektra/kdb.h> and "elektra/kdb.h".
The configure_file and install commands in the CMakeLists.txt were moved/updated.
For custom target elektra_config_headers the path of kdb.h was updated.
Resolving ElektraInitiative#817

src/include/CMakeLists.txt

@@ -157,8 +157,6 @@ endif (ENABLE_OPTIMIZATIONS)
 
 test_big_endian (ELEKTRA_BIG_ENDIAN)
 
-configure_file ("${CMAKE_CURRENT_SOURCE_DIR}/kdb.h.in" "${CMAKE_CURRENT_BINARY_DIR}/kdb.h")
-
 configure_file ("${CMAKE_CURRENT_SOURCE_DIR}/kdbconfig.h.in" "${CMAKE_CURRENT_BINARY_DIR}/kdbconfig.h")
 
 configure_file ("${CMAKE_CURRENT_SOURCE_DIR}/kdbversion.h.in" "${CMAKE_CURRENT_BINARY_DIR}/kdbversion.h")
@@ -170,7 +168,6 @@ install (
 	      kdbease.h
 	      "${CMAKE_CURRENT_BINARY_DIR}/kdbtypes.h"
 	      kdbhelper.h
-	      "${CMAKE_CURRENT_BINARY_DIR}/kdb.h"
 	      kdbmodule.h
 	      kdbos.h
 	      kdbopts.h
@@ -190,7 +187,7 @@ install (
 	      kdbmerge.h
 	DESTINATION include/${TARGET_INCLUDE_FOLDER})
 
-add_custom_target (elektra_config_headers ALL DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/kdb.h ${CMAKE_CURRENT_BINARY_DIR}/kdbconfig.h
+add_custom_target (elektra_config_headers ALL DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/elektra/kdb.h ${CMAKE_CURRENT_BINARY_DIR}/kdbconfig.h
 						      ${CMAKE_CURRENT_BINARY_DIR}/kdbversion.h)
 
 add_subdirectory (kdbio)

src/include/elektra/CMakeLists.txt

@@ -1 +1,8 @@
-install (FILES error.h conversion.h types.h DESTINATION include/${TARGET_INCLUDE_FOLDER}/elektra)
+configure_file ("${CMAKE_CURRENT_SOURCE_DIR}/kdb.h.in" "${CMAKE_CURRENT_BINARY_DIR}/kdb.h")
+
+install (FILES "${CMAKE_CURRENT_BINARY_DIR}/kdb.h" DESTINATION include/${TARGET_INCLUDE_FOLDER})
+
+install (FILES error.h
+	       conversion.h
+	       types.h
+	 DESTINATION include/${TARGET_INCLUDE_FOLDER}/elektra)