Add duktapeConfig.cmake to ease configuration.

Used for reference:
https://github.com/microsoft/vcpkg/blob/master/ports/duktape/duktapeConfig.cmake.in

CMakeLists.txt

@@ -9,8 +9,10 @@ project(openrct2 CXX)
 include(cmake/platform.cmake)
 include(CMakeDependentOption)
 
+# vcpkg includes its own copy of duktapeConfig.cmake; only include ours as needed.
 if (NOT MSVC)
     include(FindPkgConfig)
+    set(CMAKE_PREFIX_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake;${CMAKE_MODULE_PATH}")
 endif ()
 include(CheckCXXCompilerFlag)
 include(GNUInstallDirs)

cmake/duktapeConfig.cmake

@@ -0,0 +1,37 @@
+# This file was obtained from:
+# https://github.com/microsoft/vcpkg/blob/master/ports/duktape/duktapeConfig.cmake.in
+# It is used under the terms of the MIT License.
+
+# - Try to find duktape
+# Once done this will define
+#
+#  DUKTAPE_FOUND - system has Duktape
+#  DUKTAPE_INCLUDE_DIRS - the Duktape include directory
+#  DUKTAPE_LIBRARIES - Link these to use DUKTAPE
+#  DUKTAPE_DEFINITIONS - Compiler switches required for using Duktape
+#
+
+find_package(PkgConfig QUIET)
+pkg_check_modules(PC_DUK QUIET duktape libduktape)
+
+find_path(DUKTAPE_INCLUDE_DIR duktape.h
+    HINTS ${PC_DUK_INCLUDEDIR} ${PC_DUK_INCLUDE_DIRS}
+    PATH_SUFFIXES duktape)
+
+find_library(DUKTAPE_LIBRARY
+    NAMES duktape libduktape
+    HINTS ${PC_DUK_LIBDIR} ${PC_DUK_LIBRARY_DIRS})
+
+include(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(duktape
+    REQUIRED_VARS DUKTAPE_LIBRARY DUKTAPE_INCLUDE_DIR)
+
+if (DUKTAPE_FOUND)
+    set (DUKTAPE_LIBRARIES ${DUKTAPE_LIBRARY})
+    set (DUKTAPE_INCLUDE_DIRS ${DUKTAPE_INCLUDE_DIR} )
+endif ()
+
+MARK_AS_ADVANCED(
+    DUKTAPE_INCLUDE_DIR
+    DUKTAPE_LIBRARY
+)

src/openrct2/CMakeLists.txt

@@ -101,16 +101,12 @@ if (NOT DISABLE_GOOGLE_BENCHMARK)
 endif ()
 
 if (ENABLE_SCRIPTING)
-    if (MSVC)
-        find_package(duktape REQUIRED)
+    find_package(duktape CONFIG REQUIRED)
+    include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${DUKTAPE_INCLUDE_DIRS})
+    if (STATIC)
+        target_link_libraries(${PROJECT_NAME} ${DUKTAPE_STATIC_LIBRARY})
     else ()
-        PKG_CHECK_MODULES(DUKTAPE REQUIRED duktape)
-        target_include_directories(${PROJECT_NAME} PRIVATE ${DUKTAPE_INCLUDE_DIRS})
-        if (STATIC)
-            target_link_libraries(${PROJECT_NAME} ${DUKTAPE_STATIC_LIBRARIES})
-        else ()
-            target_link_libraries(${PROJECT_NAME} ${DUKTAPE_LIBRARIES})
-        endif ()
+        target_link_libraries(${PROJECT_NAME} ${DUKTAPE_LIBRARY})
     endif ()
 endif ()