Use FindLibrary() cmake command to properly locate the library, even if the...

Use FindLibrary() cmake command to properly locate the library, even if the directory is already known. This is needed to get the proper full path reference to the library.

cmake/FindPROJECT_NAME.cmake.in.in

@@ -6,19 +6,27 @@
 #   @PROJECT_NAME@_VERSION      : the package version
 #   @PROJECT_NAME@_INCLUDE_DIRS : path to the include directory
 #   @PROJECT_NAME@_LIBRARY_DIRS : path to the library directory
-#   @PROJECT_NAME@_LIBRARIES    : the provided libraries
+#   @PROJECT_NAME@_LIBRARIES    : additional libraries the depending project needs to link against. The library provided
+#                                 by the package @PROJECT_NAME@ will be added automatically
 #   @PROJECT_NAME@_CXX_FLAGS    : additional C++ compiler flags
 #   @PROJECT_NAME@_LINKER_FLAGS : additional linker flags
 #
 # @author Martin Killenberg, DESY
 #
 
+# The library itself must be "searched" using the FIND_LIBRARY command in the known install directory, to set
+# the variable properly
+FIND_LIBRARY(@PROJECT_NAME@_LIBRARY @PROJECT_NAME@
+  @CMAKE_INSTALL_PREFIX@/lib
+  NO_DEFAULT_PATH
+)
+
 # Since this file is already part of the installation to be found, the configuration can be hard-coded at
 # installation time
 set(@PROJECT_NAME@_VERSION "@@PROJECT_NAME@_SOVERSION@")
 set(@PROJECT_NAME@_INCLUDE_DIRS @@PROJECT_NAME@_INCLUDE_DIRS@)
 set(@PROJECT_NAME@_LIBRARY_DIRS @@PROJECT_NAME@_LIBRARY_DIRS@)
-set(@PROJECT_NAME@_LIBRARIES @@PROJECT_NAME@_LIBRARIES@)
+set(@PROJECT_NAME@_LIBRARIES ${@PROJECT_NAME@_LIBRARY} @@PROJECT_NAME@_LIBRARIES@)
 set(@PROJECT_NAME@_CXX_FLAGS "@@PROJECT_NAME@_CXX_FLAGS@")
 set(@PROJECT_NAME@_LINKER_FLAGS "@@PROJECT_NAME@_LINKER_FLAGS@")