From cc52ef8ed3b75a581262c587f6c06c213a550f86 Mon Sep 17 00:00:00 2001
From: Lasse Collin <lasse.collin@tukaani.org>
Date: Sat, 15 Jun 2024 18:07:04 +0300
Subject: [PATCH] CMake: Use the same option list for XZ_THREADS as in
 configure.ac

Also clarify that "yes" will fail if no threading support is found.
If no threading is wanted, it has to be disabled manually.

configure.ac doesn't behave this way at the moment. Instead it
assumes pthreads to be present if not targeting Windows. If pthreads
actually are missing, the build fails later.
---
 CMakeLists.txt | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 01ca48a7..94842e1d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -634,18 +634,20 @@ endforeach()
 #############
 
 # Supported threading methods:
-# ON    - autodetect the best threading method. The autodetection will
+# yes   - Autodetect the best threading method. The autodetection will
 #         prefer Windows threading (win95 or vista) over posix if both are
 #         available. vista threads will be used over win95 unless it is a
-#         32-bit build.
-# OFF   - Disable threading.
+#         32-bit build. Configuration fails if no threading support is found;
+#         threading won't be silently disabled.
+# no    - Disable threading.
 # posix - Use posix threading (pthreads), or throw an error if not available.
 # win95 - Use Windows win95 threading, or throw an error if not available.
 # vista - Use Windows vista threading, or throw an error if not available.
-set(SUPPORTED_THREADING_METHODS ON OFF posix win95 vista)
+set(SUPPORTED_THREADING_METHODS yes no posix win95 vista)
 
-set(XZ_THREADS ON CACHE STRING
-    "Threading method: Set to 'ON' to autodetect, 'OFF' to disable threading.")
+set(XZ_THREADS yes CACHE STRING "Threading method: \
+'yes' to autodetect, 'no' to disable, 'posix' (pthreads), \
+'win95' (WinXP compatible), 'vista' (needs Windows Vista or later)")
 
 # Create dropdown in CMake GUI since only 1 threading method is possible
 # to select in a build.
@@ -676,7 +678,7 @@ if(XZ_THREADS)
     # Note that on Cygwin CMAKE_USE_WIN32_THREADS_INIT is false.
     if(CMAKE_USE_WIN32_THREADS_INIT AND NOT XZ_THREADS STREQUAL "posix")
         if(XZ_THREADS STREQUAL "win95"
-                OR (XZ_THREADS STREQUAL "ON" AND CMAKE_SIZEOF_VOID_P EQUAL 4))
+                OR (XZ_THREADS STREQUAL "yes" AND CMAKE_SIZEOF_VOID_P EQUAL 4))
             # Use Windows 95 (and thus XP) compatible threads.
             # This avoids use of features that were added in
             # Windows Vista. This is used for 32-bit x86 builds for
@@ -688,7 +690,7 @@ if(XZ_THREADS)
             add_compile_definitions(MYTHREAD_VISTA)
         endif()
     elseif(CMAKE_USE_PTHREADS_INIT)
-        if(XZ_THREADS STREQUAL "posix" OR XZ_THREADS STREQUAL "ON")
+        if(XZ_THREADS STREQUAL "posix" OR XZ_THREADS STREQUAL "yes")
             # The threading library only needs to be explicitly linked
             # for posix threads, so this is needed for creating
             # liblzma-config.cmake later.