build: port set_utils and dependency_utils from oiio cmake scripts (#1845)

For those who didn't see this get added in OIIO land a few months
back, the highlights are:

* set_utils.cmake -- variable setting utilities, including
  replacements/wrappers for set(CACHE) and option() that have a few
  extra bells and whistles, including that they allow environment
  variables of the same name to override the default values.

* dependency_utils.cmake -- moved the prior contents of
  checked_find_package.cmake here, added more features, including...

* An end-of-config dependency report that prints which dependencies
  were found and their versions, which were found but were too old,
  which were missing.

* The skeleton of an automatic local dependency build facility.  The
  short story is that if a dependency is not found or is too old AND
  it can find a file called src/cmake/build_PACKAGE.cmake, it will run
  that file and expect it to download and build the dependency on the
  fly. I haven't added any of those scripts here yet, but on the OIIO
  side we already have a few to build certain critical dependencies.
  Future PRs to OSL will also add the missing pieces to build the
  dependencies.

Signed-off-by: Larry Gritz <lg@larrygritz.com>

Author: lgritz

CMakeLists.txt

@@ -39,6 +39,28 @@ if (CMAKE_VERSION VERSION_LESS 3.21)
     endif ()
 endif ()
 
+# Set up module path for our own cmake modules and add some esential ones
+list (APPEND CMAKE_MODULE_PATH
+      "${PROJECT_SOURCE_DIR}/src/cmake/modules"
+      "${PROJECT_SOURCE_DIR}/src/cmake")
+
+# Utilities
+include (colors)
+include (set_utils)
+include (check_is_enabled)
+include (fancy_add_executable)
+
+# If the user wants to use Conan to build dependencies, they will have done
+# this prior to the cmake config:
+#   cd <build area>
+#   conan install <source area>
+# and that will leave a conanbuildinfo.cmake in the build area for us.
+if (EXISTS ${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
+    include (${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
+    message (STATUS "Using Conan for dependencies")
+    conan_basic_setup()
+endif()
+
 if (NOT CMAKE_BUILD_TYPE)
     set (CMAKE_BUILD_TYPE "Release")
 endif ()
@@ -60,6 +82,7 @@ message (STATUS "Project build dir      = ${CMAKE_BINARY_DIR}")
 message (STATUS "Project install prefix = ${CMAKE_INSTALL_PREFIX}")
 message (STATUS "Configuration types    = ${CMAKE_CONFIGURATION_TYPES}")
 message (STATUS "Build type             = ${CMAKE_BUILD_TYPE}")
+message (STATUS "Supported release      = ${${PROJECT_NAME}_SUPPORTED_RELEASE}")
 
 # Make the build area layout look a bit more like the final dist layout
 set (CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
@@ -70,7 +93,6 @@ if ("${PROJECT_SOURCE_DIR}" STREQUAL "${CMAKE_BINARY_DIR}")
     message (FATAL_ERROR "Not allowed to run in-source build!")
 endif ()
 
-
 option (CMAKE_USE_FOLDERS "Use the FOLDER target property to organize targets into folders." ON)
 mark_as_advanced (CMAKE_USE_FOLDERS)
 if (CMAKE_USE_FOLDERS)
@@ -158,22 +180,24 @@ if (${PROJ_NAME}_NAMESPACE_INCLUDE_PATCH)
 endif ()
 message(STATUS "Setting Namespace to: ${PROJ_NAMESPACE_V}")
 
+# Define OSL_INTERNAL symbol only when building OSL itself, will not be
+# defined for downstream projects using OSL.
+add_definitions (-DOSL_INTERNAL=1)
 
-list (APPEND CMAKE_MODULE_PATH
-      "${PROJECT_SOURCE_DIR}/src/cmake/modules"
-      "${PROJECT_SOURCE_DIR}/src/cmake")
-
-# Helpful functions and macros for our project
-include (colors)
-include (check_is_enabled)
-include (checked_find_package)
+# To make sure we aren't relying on deprecated OIIO features, we define
+# OIIO_DISABLE_DEPRECATED before including any OIIO headers.
+add_definitions (-DOIIO_DISABLE_DEPRECATED=900000)
 
 # All the C++ and compiler related options and adjustments
 include (compiler)
 
+# Dependency finding utilities and all dependency-related options
+include (dependency_utils)
+
 # Utilities and options related to finding python and making python bindings
 include (pythonutils)
 
+# Dependency finding utilities and all dependency-related options
 include (externalpackages)
 include (flexbison)
 include (cuda_macros)
@@ -311,3 +335,5 @@ endif ()
 if (PROJECT_IS_TOP_LEVEL)
     include (packaging)
 endif ()
+
+print_package_notfound_report ()

src/cmake/checked_find_package.cmake

@@ -9,4 +9,9 @@ set (ColorReset       "${ColorEsc}[m")
 set (ColorRed         "${ColorEsc}[31m")
 set (ColorGreen       "${ColorEsc}[32m")
 set (ColorYellow      "${ColorEsc}[33m")
+set (ColorBlue        "${ColorEsc}[34m")
+set (ColorMagenta     "${ColorEsc}[35m")
+set (ColorBoldRed     "${ColorEsc}[1;31m")
+set (ColorBoldGreen   "${ColorEsc}[1;32m")
+set (ColorBoldYellow  "${ColorEsc}[1;33m")
 set (ColorBoldWhite   "${ColorEsc}[1;37m")