Bring the H5detect removal change from develop (#3648)

* Bring the H5detect removal change from develop

- Removed CMake cross-compiling variables                                    
                                                                             
  * HDF5_USE_PREGEN                                                          
  * HDF5_BATCH_H5DETECT                                                      
                                                                             
  These were used to work around H5detect and H5make_libsettings and         
  are no longer required.                                                    
                                                                             
- Running H5make_libsettings is no longer required for cross-compiling       
                                                                             
  The functionality of H5make_libsettings is now handled via template files, 
  so H5make_libsettings has been removed.                                    
                                                                             
- Running H5detect is no longer required for cross-compiling                 
                                                                             
  The functionality of H5detect is now exercised at library startup,         
  so H5detect has been removed.

* Put H5T_CONV_ab macros in do..while loops (#3432)

Ever since a recent round of macro cleanup, bin/trace and clang-format
have been bickering over what H5Tconv.c should look like and neither
produces readable code.

This change puts the top-level H5T_CONV_ab macros in do..while loops,
adds appropriate semicolons, and adds the missing H5_CLANG_DIAG_ON|OFF
and H5_GCC_CLANG_DIAG_ON|OFF macros to the list of statement macros
clang-format recognizes. H5Tconv.c is now readable and both bin/trace
and clang-format are happy.

3 files changed, 18 insertions, 28 deletions

diff --git a/release_docs/INSTALL_CMake.txt b/release_docs/INSTALL_CMake.txt
index 4da4daa..9e0797b 100644
--- a/release_docs/INSTALL_CMake.txt
+++ b/release_docs/INSTALL_CMake.txt
@@ -1030,15 +1030,6 @@ References:
     https://stackoverflow.com/questions/54539682/how-to-set-up-cmake-to-cross-compile-with-clang-for-arm-embedded-on-windows?rq=1
     https://developer.android.com/ndk/guides/cmake
 
-Predefine H5Tinit.c file
--------------------------------
-The one file that needs to be pre-generated is the H5Tinit.c file. The variables
-indicated in the error log (see above) are the variables that need to match the target system.
-
-The HDF5 CMake variables;
-    HDF5_USE_PREGEN: set this to true
-    HDF5_USE_PREGEN_DIR: set this path to the preset H5Tinit.c file
-
 
 ========================================================================
 X:    Using CMakePresets.json for compiling
diff --git a/release_docs/README_HPC b/release_docs/README_HPC
index 27dc32c..576e019 100644
--- a/release_docs/README_HPC
+++ b/release_docs/README_HPC
@@ -9,7 +9,6 @@ Section II:    Obtain HDF5 source
 Section III:   Using ctest command to build and test
 Section IV:    Cross compiling
 Section V:     Manual alternatives
-Section VI:    Other cross compiling options
 
 ************************************************************************
 
@@ -184,21 +183,3 @@ or
 for parallel builds.
 
 Tests on machines using LSF will typically use "bsub ctestS.lsf", etc.
-
-========================================================================
-VI.    Other cross compiling options
-========================================================================
-Settings for two other cross-compiling options are also in the config/toolchain
-files which do not seem to be necessary with the Cray PrgEnv-* modules
-
-1.  HDF5_USE_PREGEN.  This option, along with the HDF5_USE_PREGEN_DIR CMake
-    variable would allow the use of an appropriate H5Tinit.c file with type
-    information generated on a compute node to be used when cross compiling
-    for those compute nodes.  The use of the variables in lines 110 and 111
-    of HDF5options.cmake file seem to preclude needing this option with the
-    available Cray modules and CMake option.
-
-2.  HDF5_BATCH_H5DETECT and associated CMake variables.  This option when
-    properly configured will run H5detect in a batch job on a compute node
-    at the beginning of the CMake build process.  It was also found to be
-    unnecessary with the available Cray modules and CMake options.
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 57e8189..f68775c 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -47,6 +47,24 @@ New Features
 
     Configuration:
     -------------
+    - Removed CMake cross-compiling variables
+
+      * HDF5_USE_PREGEN
+      * HDF5_BATCH_H5DETECT
+
+      These were used to work around H5detect and H5make_libsettings and
+      are no longer required.
+
+    - Running H5make_libsettings is no longer required for cross-compiling
+
+      The functionality of H5make_libsettings is now handled via template files,
+      so H5make_libsettings has been removed.
+
+    - Running H5detect is no longer required for cross-compiling
+
+      The functionality of H5detect is now exercised at library startup,
+      so H5detect has been removed.
+
     - Thread-safety + static library disabled on Windows w/ CMake
 
       The thread-safety feature requires hooks in DllMain(), which is only