From 883cbbee35c60a803cb9f2ca3df472fbd5db46ff Mon Sep 17 00:00:00 2001
From: Quincey Koziol <quincey@koziol.cc>
Date: Wed, 20 Nov 2024 16:52:07 -0500
Subject: [PATCH] Revert changes for detecting C11 threads

Signed-off-by: Quincey Koziol <quincey@koziol.cc>
---
 CMakeLists.txt     | 52 ++++++++++++++++++++--------------------------
 configure.ac       |  2 +-
 src/CMakeLists.txt |  5 +++--
 3 files changed, 26 insertions(+), 33 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c6cc25468dc..73dc2d3ee28 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -794,43 +794,35 @@ endif ()
 
 # Determine if a threading package is available on this system
 option (HDF5_ENABLE_THREADS "Enable thread support" ON)
-if (HDF5_ENABLE_THREADS)
-  # When C11 threads are available, those are the top choice
-  CHECK_INCLUDE_FILE("threads.h" HAVE_THREADS_H)
-  if (HAVE_THREADS_H)
-    set (H5_HAVE_C11_THREADS 1)
-  else()
-    # Determine which threading package to use
-    set (THREADS_PREFER_PTHREAD_FLAG ON)
-    find_package (Threads)
-
-    if (Threads_FOUND)
-      # When Win32 is available, we use those threads
-      if (WIN32)
-        set (H5_HAVE_WIN_THREADS 1)
-      else()
-        if (CMAKE_USE_PTHREADS_INIT)
-          set (H5_HAVE_PTHREAD_H 1)
-        else()
-          message (FATAL_ERROR " **** thread support requires C11 threads, Win32 threads or Pthreads **** ")
-        endif()
-      endif()
-
-      set (CMAKE_REQUIRED_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
-    else()
-      message (FATAL_ERROR " **** thread support requires C11 threads, Win32 threads or Pthreads **** ")
-    endif()
-  endif()
-
-  # Threads are available
+set (THREADS_PREFER_PTHREAD_FLAG ON)
+find_package (Threads)
+if (Threads_FOUND)
   set (H5_HAVE_THREADS 1)
+  set (CMAKE_REQUIRED_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
+
+  # Determine which threading package to use
+  # Comment out check for C11 threads for now, since it conflicts with the
+  # current --std=c99 compile flags at configuration time.  When we switch to
+  # --std=c11, this can be uncommented.
+  #CHECK_INCLUDE_FILE("threads.h" HAVE_THREADS_H)
+  if (WIN32)
+    # When Win32 is available, we use those threads
+    set (H5_HAVE_WIN_THREADS 1)
+  elseif (HAVE_THREADS_H)
+    # When C11 threads are available, those are the top choice
+    set (H5_HAVE_C11_THREADS 1)
+  elseif (CMAKE_USE_PTHREADS_INIT)
+    set (H5_HAVE_PTHREAD_H 1)
+  else ()
+    message (FATAL_ERROR " **** thread support requires C11 threads, Win32 threads or Pthreads **** ")
+  endif ()
 
   # Check for compiler support for atomic variables
   CHECK_INCLUDE_FILE("stdatomic.h" HAVE_STDATOMIC_H)
   if (HAVE_STDATOMIC_H)
     set (H5_HAVE_STDATOMIC_H 1)
   endif()
-endif()
+endif ()
 
 # Determine whether to build the HDF5 Subfiling VFD
 set (H5FD_SUBFILING_DIR ${HDF5_SRC_DIR}/H5FDsubfiling)
diff --git a/configure.ac b/configure.ac
index 82a3febf370..72bc8f91b76 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2237,7 +2237,7 @@ if test "X$THREADS" = "Xyes"; then
     # Comment out check for C11 threads for now, since it conflicts with the
     # current --std=c99 compile flags at configuration time.  When we switch to
     # --std=c11, this can be uncommented.
-    AC_CHECK_HEADERS([threads.h],[HAVE_THREADS_H="yes"],[HAVE_THREADS_H="no"])
+    #AC_CHECK_HEADERS([threads.h],[HAVE_THREADS_H="yes"],[HAVE_THREADS_H="no"])
     if test "x$HAVE_THREADS_H" = "xyes"; then
         # Default or no --> C11 threads
         if test "$withval" = "default" -o "$withval" = "no" ; then
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index eb50ba4f3e9..9afa502c990 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -647,6 +647,7 @@ set (H5TS_SOURCES
     ${HDF5_SRC_DIR}/H5TSbarrier.c
     ${HDF5_SRC_DIR}/H5TSc11.c
     ${HDF5_SRC_DIR}/H5TScond.c
+    ${HDF5_SRC_DIR}/H5TSdlftt_mutex.c
     ${HDF5_SRC_DIR}/H5TSint.c
     ${HDF5_SRC_DIR}/H5TSkey.c
     ${HDF5_SRC_DIR}/H5TSmutex.c
@@ -1113,7 +1114,7 @@ if (BUILD_STATIC_LIBS)
   )
   if (NOT WIN32)
     target_link_libraries (${HDF5_LIB_TARGET}
-      PRIVATE "$<$<OR:$<BOOL:${HDF5_ENABLE_THREADS}>,$<BOOL:${HDF5_ENABLE_SUBFILING_VFD}>>:${CMAKE_THREAD_LIBS_INIT}>"
+      PRIVATE "$<$<OR:$<BOOL:${HDF5_ENABLE_THREADS}>,$<BOOL:${HDF5_ENABLE_SUBFILING_VFD}>>:Threads::Threads>"
     )
   endif ()
   set_global_variable (HDF5_LIBRARIES_TO_EXPORT ${HDF5_LIB_TARGET})
@@ -1145,7 +1146,7 @@ if (BUILD_SHARED_LIBS)
   TARGET_C_PROPERTIES (${HDF5_LIBSH_TARGET} SHARED)
   target_link_libraries (${HDF5_LIBSH_TARGET}
       PRIVATE ${LINK_LIBS} ${LINK_COMP_LIBS}
-      PUBLIC "$<$<PLATFORM_ID:Windows>:${LINK_PUB_LIBS}>" "$<$<NOT:$<PLATFORM_ID:Windows>>:${CMAKE_DL_LIBS}>" "$<$<BOOL:${HDF5_ENABLE_PARALLEL}>:MPI::MPI_C>" "$<$<OR:$<BOOL:${HDF5_ENABLE_THREADS}>,$<BOOL:${HDF5_ENABLE_SUBFILING_VFD}>>:${CMAKE_THREAD_LIBS_INIT}>"
+      PUBLIC "$<$<PLATFORM_ID:Windows>:${LINK_PUB_LIBS}>" "$<$<NOT:$<PLATFORM_ID:Windows>>:${CMAKE_DL_LIBS}>" "$<$<BOOL:${HDF5_ENABLE_PARALLEL}>:MPI::MPI_C>" "$<$<OR:$<BOOL:${HDF5_ENABLE_THREADS}>,$<BOOL:${HDF5_ENABLE_SUBFILING_VFD}>>:Threads::Threads>"
   )
   set_global_variable (HDF5_LIBRARIES_TO_EXPORT "${HDF5_LIBRARIES_TO_EXPORT};${HDF5_LIBSH_TARGET}")
   H5_SET_LIB_OPTIONS (${HDF5_LIBSH_TARGET} ${HDF5_LIB_NAME} SHARED "LIB")