build: add OpenSSL find_package dispatcher

Refactor openssl.cmake to use the find-first dispatcher pattern:
- RV_FIND_DEPENDENCY with ALLOW_MODULE and PKG_CONFIG_NAME for
  CONFIG → MODULE (FindOpenSSL) → pkg-config resolution
- Extract ExternalProject_Add build logic into build/openssl.cmake
- Preserve RHEL8/CY2023 system OpenSSL 1.1.1 path
- Use TARGET_LIBS for found-package staging
- Linux OpenSSL/ subdirectory isolation for RHEL ABI compatibility
- Shared naming logic for both found and built paths

Author: cedrik-fuoco-adsk

cmake/dependencies/build/openssl.cmake

@@ -0,0 +1,129 @@
+#
+# Copyright (C) 2022  Autodesk, Inc. All Rights Reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+SET(RV_DEPS_WIN_PERL_ROOT
+    ""
+    CACHE STRING "Path to Windows perl root"
+)
+
+STRING(REPLACE "." "_" _version_underscored ${_version})
+
+IF(RV_TARGET_WINDOWS
+   AND (NOT RV_DEPS_WIN_PERL_ROOT
+        OR RV_DEPS_WIN_PERL_ROOT STREQUAL "")
+)
+  MESSAGE(
+    FATAL_ERROR
+      "Unable to build without a RV_DEPS_WIN_PERL_ROOT. OpenSSL requires a Windows native perl interpreter to build (it recommends https://strawberryperl.com/). Example -DRV_DEPS_WIN_PERL_ROOT=c:/Strawberry/perl/bin"
+  )
+ENDIF()
+
+SET(_make_command_script
+    "${PROJECT_SOURCE_DIR}/src/build/make_openssl.py"
+)
+SET(_make_command
+    python3 "${_make_command_script}"
+)
+
+LIST(APPEND _make_command "--source-dir")
+LIST(APPEND _make_command ${_source_dir})
+LIST(APPEND _make_command "--output-dir")
+LIST(APPEND _make_command ${_install_dir})
+
+LIST(APPEND _make_command "--vfx_platform")
+LIST(APPEND _make_command ${RV_VFX_CY_YEAR})
+
+IF(RV_TARGET_WINDOWS)
+  LIST(APPEND _make_command "--perlroot")
+  LIST(APPEND _make_command ${RV_DEPS_WIN_PERL_ROOT})
+ENDIF()
+
+IF(APPLE)
+  IF(RV_TARGET_APPLE_X86_64)
+    SET(__openssl_arch__
+        x86_64
+    )
+  ELSEIF(RV_TARGET_APPLE_ARM64)
+    SET(__openssl_arch__
+        arm64
+    )
+  ENDIF()
+  LIST(APPEND _make_command --arch=-${__openssl_arch__})
+ENDIF()
+
+EXTERNALPROJECT_ADD(
+  ${_target}
+  DOWNLOAD_NAME ${_target}_${_version}.zip
+  DOWNLOAD_DIR ${RV_DEPS_DOWNLOAD_DIR}
+  DOWNLOAD_EXTRACT_TIMESTAMP TRUE
+  SOURCE_DIR ${_source_dir}
+  INSTALL_DIR ${_install_dir}
+  URL ${_download_url}
+  URL_MD5 ${_download_hash}
+  CONFIGURE_COMMAND ${_make_command} --configure
+  BUILD_COMMAND ${_make_command} --build
+  INSTALL_COMMAND ${_make_command} --install
+  BUILD_IN_SOURCE TRUE
+  BUILD_ALWAYS FALSE
+  BUILD_BYPRODUCTS ${_crypto_lib} ${_ssl_lib}
+  USES_TERMINAL_BUILD TRUE
+)
+
+FILE(MAKE_DIRECTORY ${_include_dir})
+
+IF(RV_TARGET_WINDOWS)
+  ADD_CUSTOM_COMMAND(
+    TARGET ${_target}
+    POST_BUILD
+    COMMENT "Renaming the openssl import libs to the name FFmpeg is expecting"
+    COMMAND ${CMAKE_COMMAND} -E copy ${_install_dir}/lib/libssl.lib ${_lib_dir}/ssl.lib
+    COMMAND ${CMAKE_COMMAND} -E copy ${_install_dir}/lib/libcrypto.lib ${_lib_dir}/crypto.lib
+  )
+ENDIF()
+
+ADD_LIBRARY(OpenSSL::Crypto SHARED IMPORTED GLOBAL)
+ADD_DEPENDENCIES(OpenSSL::Crypto ${_target})
+SET_PROPERTY(
+  TARGET OpenSSL::Crypto
+  PROPERTY IMPORTED_LOCATION ${_crypto_lib}
+)
+SET_PROPERTY(
+  TARGET OpenSSL::Crypto
+  PROPERTY IMPORTED_SONAME ${_crypto_lib_name}
+)
+IF(RV_TARGET_WINDOWS)
+  SET_PROPERTY(
+    TARGET OpenSSL::Crypto
+    PROPERTY IMPORTED_IMPLIB ${_implibpath_crypto}
+  )
+ENDIF()
+TARGET_INCLUDE_DIRECTORIES(
+  OpenSSL::Crypto
+  INTERFACE ${_include_dir}
+)
+LIST(APPEND RV_DEPS_LIST OpenSSL::Crypto)
+
+ADD_LIBRARY(OpenSSL::SSL SHARED IMPORTED GLOBAL)
+ADD_DEPENDENCIES(OpenSSL::SSL ${_target})
+SET_PROPERTY(
+  TARGET OpenSSL::SSL
+  PROPERTY IMPORTED_LOCATION ${_ssl_lib}
+)
+SET_PROPERTY(
+  TARGET OpenSSL::SSL
+  PROPERTY IMPORTED_SONAME ${_ssl_lib_name}
+)
+IF(RV_TARGET_WINDOWS)
+  SET_PROPERTY(
+    TARGET OpenSSL::SSL
+    PROPERTY IMPORTED_IMPLIB ${_implibpath_ssl}
+  )
+ENDIF()
+TARGET_INCLUDE_DIRECTORIES(
+  OpenSSL::SSL
+  INTERFACE ${_include_dir}
+)
+LIST(APPEND RV_DEPS_LIST OpenSSL::SSL)