Auto-download Saigo SDK for any supported host

The old PNaCl toolchain has been being shipped as part of the deps
package, with the host platform for the compilers assumed to be the same
as the target platform of the deps package. Experimental Saigo support
has thus far required manually downloading the SDK. Now, make the Saigo
toolchain auto-downloadable (if USE_NACL_SAIGO=1) independently from the
target platform dependencies.  This has several advantages:
- No need to download the NaCl toolchain if you are not building NaCl.
- No need to download a useless NaCl toolchain when cross-compiling.
- Toolchain can be downloaded for host systems that don't have a deps
  package, or where the deps package being used doesn't match the real
  host system.  (The SDK is available for more systems than the deps
  package.)

The toolchain is downloaded from Github and then, like the deps package,
extracted into external_deps/.

Author: slipher

CMakeLists.txt

@@ -157,6 +157,12 @@ set(NACL_VM_INHERITED_OPTIONS "${DEFAULT_NACL_VM_INHERITED_OPTIONS}" CACHE STRIN
     "Semicolon-separated list of options for which NaCl game VMs should use the same value as the other binaries")
 mark_as_advanced(NACL_VM_INHERITED_OPTIONS)
 
+# Warning: changing SAIGOSDK_ROOT/SAIGOSDK_VERSION after subprojects have been configured WILL
+# change the compiler, but it is a bad idea since flag tests and such (not to mention the actual
+# compiled artifacts) will be out of date.
+set(SAIGOSDK_ROOT "" CACHE PATH "Override Saigo NaCl SDK path")
+mark_as_advanced(SAIGOSDK_ROOT)
+
 ################################################################################
 # Directories
 ################################################################################
@@ -189,8 +195,9 @@ else()
     set(FULL_OUTPUT_DIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR})
 endif()
 
-# Dependencies version, this must match the number in external_deps/build.sh
-set(DEPS_VERSION 11)
+# Dependencies versions
+set(DEPS_VERSION 11) # This must match the number in external_deps/build.sh
+set(SAIGOSDK_VERSION 20260925)
 
 option(USE_EXTERNAL_DEPS "Download or reuse dependencies from EXTERNAL_DEPS_DIR (mandatory for building and running NaCl .nexe binaries)." ON)
 
@@ -263,9 +270,6 @@ if (USE_EXTERNAL_DEPS AND NOT YOKAI_TARGET_SYSTEM_NACL)
     endif()
 endif()
 
-set(SAIGOSDK_ROOT "${DEPS_DIR}/saigo_newlib" CACHE PATH "Saigo NaCl SDK path")
-mark_as_advanced(SAIGOSDK_ROOT)
-
 option(USE_EXTERNAL_DEPS_LIBS "Build and link against libraries from the EXTERNAL_DEPS_DIR" ${DEFAULT_USE_EXTERNAL_DEPS_LIBS})
 
 if (USE_EXTERNAL_DEPS AND NOT YOKAI_TARGET_SYSTEM_NACL)
@@ -445,6 +449,11 @@ if (DEPS_DIR)
         endif()
     endif()
 
+    if (BUILD_GAME_NACL AND USE_NACL_SAIGO AND NOT SAIGOSDK_ROOT)
+        include(DaemonDependenciesDownload)
+        download_saigosdk()
+    endif()
+
     if (USE_EXTERNAL_DEPS_LIBS)
         # Add to paths
         set(CMAKE_FIND_ROOT_PATH ${DEPS_DIR} ${CMAKE_FIND_ROOT_PATH})

cmake/DaemonDependenciesDownload.cmake

@@ -0,0 +1,68 @@
+# Daemon BSD Source Code
+# Copyright (c) 2013-2026, Daemon Developers
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#  * Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#  * Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#  * Neither the name of the Daemon developers nor the
+#    names of its contributors may be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL DAEMON DEVELOPERS BE LIABLE FOR ANY
+# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# TODO: Move other deps downloading code in here.
+
+set(SAIGOSDK_BASENAME saigosdk-${DEPS_SYSTEM}-${DEPS_ARCH}_${SAIGOSDK_VERSION})
+set(SAIGOSDK_ROOT ${EXTERNAL_DEPS_DIR}/${SAIGOSDK_BASENAME})
+set(SAIGOSDK_ROOT "${SAIGOSDK_ROOT}" PARENT_SCOPE)
+
+function(download_saigosdk)
+    if (NOT EXISTS ${SAIGOSDK_ROOT})
+        set(DEPS_FILENAME "${SAIGOSDK_BASENAME}.tar.xz")
+        set(REMOTE "https://github.com/DaemonEngine/saigo-nacl-sdk/releases/download/v${SAIGOSDK_VERSION}/${DEPS_FILENAME}")
+        message(STATUS "Downloading NaCl SDK from '${REMOTE}'")
+
+        file(DOWNLOAD "${REMOTE}" "${OBJ_DIR}/${DEPS_FILENAME}"
+            SHOW_PROGRESS
+            STATUS DOWNLOAD_RESULT
+            LOG DOWNLOAD_LOG
+        )
+
+        list(GET DOWNLOAD_RESULT 0 DOWNLOAD_STATUS)
+        list(GET DOWNLOAD_RESULT 1 DOWNLOAD_STRING)
+
+        if (NOT DOWNLOAD_STATUS EQUAL 0)
+            message(FATAL_ERROR "Failed to download '${REMOTE}': This may be a network error, or your system may be an unsupported host platform.
+                Status code: ${DOWNLOAD_STATUS}
+                Error string: ${DOWNLOAD_STRING}
+                Download log: ${DOWNLOAD_LOG}"
+            )
+        endif()
+
+        message(STATUS "SDK download completed successfully")
+
+        # Extract the downloaded archive
+        execute_process(
+            COMMAND ${CMAKE_COMMAND} -E tar xJf ${OBJ_DIR}/${DEPS_FILENAME}
+            WORKING_DIRECTORY ${EXTERNAL_DEPS_DIR}
+            RESULT_VARIABLE EXTRACT_RESULT
+        )
+        if (NOT EXTRACT_RESULT EQUAL 0)
+            message(FATAL_ERROR "Could not extract ${DEPS_FILENAME}")
+        endif()
+    endif()
+endfunction()