To reduce maintenance effort, delete the `noerror-` variants of the compiler flags files (#1033)

* Avoid maintenance headaches: delete the `noerror-` variants of the
compiler flags files, since they essentially duplicate the `error-`
files modulo the replacement of `-Werror=` with `-W` and any changes in
comments.  (I verified the duplication with a script.)

For autoconf, reinstate the use of the `demote_errors` shell function to
derive the `noerror-` content from the `error-` content.  `demote_errors`
replaces `-Werror=` with `-W` when `WARNINGS_AS_ERRORS` is `no`.

Slightly reorder `configure.ac` so that the setting of
`WARNINGS_AS_ERRORS` takes effect before the `error-` files are sourced.

* Take a stab at updating the CMake files to match the changes I made to
the autoconf files to remove `noerror-` files.  I'm not much of a CMake
user so these changes are quite rough.

Looks like the duplication can be reduced with the introduction of a new
macro.

* Delete `noerror-` files from the MANIFEST.

* Reduce duplication in the CMake files: perform the
HDF5_ENABLE_WARNINGS_AS_ERRORS test once in the ADD_H5_FLAGS macro.

* Add a release note.

2 files changed, 7 insertions, 33 deletions

diff --git a/config/cmake/HDFCXXCompilerFlags.cmake b/config/cmake/HDFCXXCompilerFlags.cmake
index e76150f..7bfd0bd 100644
--- a/config/cmake/HDFCXXCompilerFlags.cmake
+++ b/config/cmake/HDFCXXCompilerFlags.cmake
@@ -133,11 +133,7 @@ else ()
         AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 4.8)
       # add the general CXX flags for g++ compiler versions 4.8 and above.
       ADD_H5_FLAGS (HDF5_CMAKE_CXX_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-general")
-      if (HDF5_ENABLE_WARNINGS_AS_ERRORS)
-        ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-error-general")
-      else ()
-        ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-noerror-general")
-      endif ()
+      ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-error-general")
     endif ()
   elseif (CMAKE_CXX_COMPILER_ID MATCHES "[Cc]lang")
     ADD_H5_FLAGS (HDF5_CMAKE_CXX_FLAGS "${HDF5_SOURCE_DIR}/config/clang-warnings/general")
@@ -201,11 +197,7 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
     # autotools always add the C flags with the CXX flags
     ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-5")
-    if (HDF5_ENABLE_WARNINGS_AS_ERRORS)
-      ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-error-5")
-    else ()
-      ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-noerror-5")
-    endif ()
+    ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-error-5")
   endif ()
 
   # Append more extra warning flags that only gcc 6.x+ knows about
@@ -230,11 +222,7 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 8.0)
     # Use the C warnings as CXX warnings are the same
     ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/8")
-    if (HDF5_ENABLE_WARNINGS_AS_ERRORS)
-      ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-8")
-    else ()
-      ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/noerror-8")
-    endif ()
+    ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-8")
     if (HDF5_ENABLE_DEV_WARNINGS)
       # Use the C warnings as CXX warnings are the same
       ADD_H5_FLAGS (H5_CXXFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/developer-8")
diff --git a/config/cmake/HDFCompilerFlags.cmake b/config/cmake/HDFCompilerFlags.cmake
index 210e475..eb43b73 100644
--- a/config/cmake/HDFCompilerFlags.cmake
+++ b/config/cmake/HDFCompilerFlags.cmake
@@ -153,22 +153,14 @@ else ()
     # Add general CFlags for GCC versions 4.8 and above
     if (CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.8)
       ADD_H5_FLAGS (HDF5_CMAKE_C_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/general")
-      if (HDF5_ENABLE_WARNINGS_AS_ERRORS)
-        ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-general")
-      else ()
-        ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/noerror-general")
-      endif ()
+      ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-general")
     endif ()
     # gcc automatically inlines based on the optimization level
     # this is just a failsafe
     list (APPEND H5_CFLAGS "-finline-functions")
   elseif (CMAKE_C_COMPILER_ID MATCHES "[Cc]lang")
     ADD_H5_FLAGS (HDF5_CMAKE_C_FLAGS "${HDF5_SOURCE_DIR}/config/clang-warnings/general")
-    if (HDF5_ENABLE_WARNINGS_AS_ERRORS)
-      ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/clang-warnings/error-general")
-    else ()
-      ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/clang-warnings/noerror-general")
-    endif ()
+    ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/clang-warnings/error-general")
   elseif (CMAKE_C_COMPILER_ID STREQUAL "PGI")
     list (APPEND HDF5_CMAKE_C_FLAGS "-Minform=inform")
   endif ()
@@ -228,11 +220,7 @@ if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
   # Append more extra warning flags that only gcc 5.x+ knows about
   if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 5.0)
     ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/5")
-    if (HDF5_ENABLE_WARNINGS_AS_ERRORS)
-      ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-5")
-    else ()
-      ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-5")
-    endif ()
+    ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-5")
   endif ()
 
   # Append more extra warning flags that only gcc 6.x+ knows about
@@ -253,9 +241,7 @@ if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
   # Append more extra warning flags that only gcc 8.x+ knows about
   if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 8.0)
     ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/8")
-    if (HDF5_ENABLE_WARNINGS_AS_ERRORS)
-      ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-8")
-    endif ()
+    ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-8")
     if (HDF5_ENABLE_DEV_WARNINGS)
       ADD_H5_FLAGS (H5_CFLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/developer-8")
     else ()