FindLibRHash: Add module to find the librhash package

Add it to a private source directory that is not installed so that we
can use it for building CMake itself.  This will allow it to mature
before being distributed publicly.

Source/Modules/FindLibRHash.cmake

@@ -0,0 +1,73 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindLibRHash
+------------
+
+Find LibRHash include directory and library.
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+An :ref:`imported target <Imported targets>` named
+``LibRHash::LibRHash`` is provided if LibRHash has been found.
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+This module defines the following variables:
+
+``LibRHash_FOUND``
+  True if LibRHash was found, false otherwise.
+``LibRHash_INCLUDE_DIRS``
+  Include directories needed to include LibRHash headers.
+``LibRHash_LIBRARIES``
+  Libraries needed to link to LibRHash.
+
+Cache Variables
+^^^^^^^^^^^^^^^
+
+This module uses the following cache variables:
+
+``LibRHash_LIBRARY``
+  The location of the LibRHash library file.
+``LibRHash_INCLUDE_DIR``
+  The location of the LibRHash include directory containing ``rhash.h``.
+
+The cache variables should not be used by project code.
+They may be set by end users to point at LibRHash components.
+#]=======================================================================]
+
+#-----------------------------------------------------------------------------
+find_library(LibRHash_LIBRARY
+  NAMES rhash
+  )
+mark_as_advanced(LibRHash_LIBRARY)
+
+find_path(LibRHash_INCLUDE_DIR
+  NAMES rhash.h
+  )
+mark_as_advanced(LibRHash_INCLUDE_DIR)
+
+#-----------------------------------------------------------------------------
+include(${CMAKE_CURRENT_LIST_DIR}/../../Modules/FindPackageHandleStandardArgs.cmake)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(LibRHash
+  FOUND_VAR LibRHash_FOUND
+  REQUIRED_VARS LibRHash_LIBRARY LibRHash_INCLUDE_DIR
+  )
+set(LIBRHASH_FOUND ${LibRHash_FOUND})
+
+#-----------------------------------------------------------------------------
+# Provide documented result variables and targets.
+if(LibRHash_FOUND)
+  set(LibRHash_INCLUDE_DIRS ${LibRHash_INCLUDE_DIR})
+  set(LibRHash_LIBRARIES ${LibRHash_LIBRARY})
+  if(NOT TARGET LibRHash::LibRHash)
+    add_library(LibRHash::LibRHash UNKNOWN IMPORTED)
+    set_target_properties(LibRHash::LibRHash PROPERTIES
+      IMPORTED_LOCATION "${LibRHash_LIBRARY}"
+      INTERFACE_INCLUDE_DIRECTORIES "${LibRHash_INCLUDE_DIRS}"
+      )
+  endif()
+endif()

Tests/CMakeLists.txt

@@ -1377,6 +1377,10 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
     add_subdirectory(FindJsonCpp)
   endif()
 
+  if(CMake_TEST_FindLibRHash)
+    add_subdirectory(FindLibRHash)
+  endif()
+
   if(CMake_TEST_FindLibUV)
     add_subdirectory(FindLibUV)
   endif()

Tests/FindLibRHash/CMakeLists.txt

@@ -0,0 +1,10 @@
+add_test(NAME FindLibRHash.Test COMMAND
+  ${CMAKE_CTEST_COMMAND} -C $<CONFIGURATION>
+  --build-and-test
+  "${CMake_SOURCE_DIR}/Tests/FindLibRHash/Test"
+  "${CMake_BINARY_DIR}/Tests/FindLibRHash/Test"
+  ${build_generator_args}
+  --build-project TestFindLibRHash
+  --build-options ${build_options}
+  --test-command ${CMAKE_CTEST_COMMAND} -V -C $<CONFIGURATION>
+  )

Tests/FindLibRHash/Test/CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.7)
+project(TestFindLibRHash C)
+include(CTest)
+
+# CMake does not actually provide FindLibRHash publicly.
+set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../../../Source/Modules)
+
+find_package(LibRHash REQUIRED)
+
+add_executable(test_librhash_tgt main.c)
+target_link_libraries(test_librhash_tgt LibRHash::LibRHash)
+add_test(NAME test_librhash_tgt COMMAND test_librhash_tgt)
+
+add_executable(test_librhash_var main.c)
+target_include_directories(test_librhash_var PRIVATE ${LibRHash_INCLUDE_DIRS})
+target_link_libraries(test_librhash_var PRIVATE ${LibRHash_LIBRARIES})
+add_test(NAME test_librhash_var COMMAND test_librhash_var)

Tests/FindLibRHash/Test/main.c

@@ -0,0 +1,7 @@
+#include <rhash.h>
+
+int main()
+{
+  rhash_library_init();
+  return 0;
+}