Build: Modernize readline finding script

(cherry picked from commit 203f1197b4)

cmake/macros/FindReadline.cmake

@@ -0,0 +1,104 @@
+# This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+
+#[=======================================================================[.rst:
+FindReadline
+-----------
+
+Find The GNU Readline Library.
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+This module defines the following :prop_tgt:`IMPORTED` targets:
+
+``Readline::Readline``
+  The Readline library, if found.
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+This module will set the following variables in your project:
+
+``READLINE_FOUND``
+  System has The GNU Readline Library.
+``READLINE_INCLUDE_DIR``
+  The Readline include directory.
+``READLINE_LIBRARY``
+  The Readline library.
+
+Hints
+^^^^^
+
+Set ``READLINE_ROOT_DIR`` to the root directory of Readline installation.
+#]=======================================================================]
+
+find_path(READLINE_INCLUDE_DIR
+  NAMES
+    readline/readline.h
+  HINTS
+    ${READLINE_ROOT_DIR}
+    ENV READLINE_ROOT_DIR
+  PATH_SUFFIXES
+    include)
+
+find_library(READLINE_LIBRARY
+  NAMES
+    readline
+  HINTS
+    ${READLINE_ROOT_DIR}
+    ENV READLINE_ROOT_DIR
+  PATH_SUFFIXES
+    lib)
+
+if(READLINE_INCLUDE_DIR AND EXISTS "${READLINE_INCLUDE_DIR}/readline/readline.h")
+  file(STRINGS "${READLINE_INCLUDE_DIR}/readline/readline.h" readline_major
+    REGEX "^#[\t ]*define[\t ]+RL_VERSION_MAJOR[\t ]+([0-9])+.*")
+  file(STRINGS "${READLINE_INCLUDE_DIR}/readline/readline.h" readline_minor
+    REGEX "^#[\t ]*define[\t ]+RL_VERSION_MINOR[\t ]+([0-9])+.*")
+  if (readline_major AND readline_minor)
+    string(REGEX REPLACE "^.*RL_VERSION_MAJOR[\t ]+([0-9])+.*$"
+           "\\1" readline_major "${readline_major}")
+    string(REGEX REPLACE "^.*RL_VERSION_MINOR[\t ]+([0-9])+.*$"
+           "\\1" readline_minor "${readline_minor}")
+    set(READLINE_VERSION "${readline_major}.${readline_minor}")
+  endif()
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Readline
+  REQUIRED_VARS
+    READLINE_LIBRARY
+    READLINE_INCLUDE_DIR
+  VERSION_VAR
+    READLINE_VERSION
+)
+
+mark_as_advanced(READLINE_FOUND READLINE_LIBRARY READLINE_INCLUDE_DIR)
+
+if(READLINE_FOUND)
+  message(STATUS "Found Readline library: ${READLINE_LIBRARY}")
+  message(STATUS "Found Readline headers: ${READLINE_INCLUDE_DIR}")
+
+  if (NOT TARGET Readline::Readline)
+    add_library(Readline::Readline UNKNOWN IMPORTED)
+    set_target_properties(Readline::Readline
+      PROPERTIES
+        IMPORTED_LOCATION
+          "${READLINE_LIBRARY}"
+        INTERFACE_INCLUDE_DIRECTORIES
+          "${READLINE_INCLUDE_DIR}")
+  endif()
+endif()

dep/readline/CMakeLists.txt

@@ -8,31 +8,12 @@
 # WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
 # implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
+add_library(readline INTERFACE)
+
 if( UNIX )
-  # find Readline (terminal input library) includes and library
-  #
-  # READLINE_INCLUDE_DIR - where the directory containing the READLINE headers can be found
-  # READLINE_LIBRARY     - full path to the READLINE library
-  find_path(READLINE_INCLUDE_DIR readline/readline.h)
-  find_library(READLINE_LIBRARY NAMES readline)
+  find_package(Readline REQUIRED)
 
-  message(STATUS "Found Readline library: ${READLINE_LIBRARY}")
-  message(STATUS "Include dir is: ${READLINE_INCLUDE_DIR}")
-
-  if (NOT READLINE_INCLUDE_DIR OR NOT READLINE_LIBRARY)
-    message(FATAL_ERROR "** Readline library not found!\n** Your distro may provide a binary for Readline e.g. for ubuntu try apt-get install libreadline5-dev")
-  endif ()
-
-  add_library(readline SHARED IMPORTED GLOBAL)
-
-  set_target_properties(readline
-    PROPERTIES
-      IMPORTED_LOCATION
-        "${READLINE_LIBRARY}"
-      INTERFACE_INCLUDE_DIRECTORIES
-        "${READLINE_INCLUDE_DIR}")
-
-else()
-  # Provide a dummy target
-  add_library(readline INTERFACE)
+  target_link_libraries(readline
+    INTERFACE
+      Readline::Readline)
 endif()