Remove Autotools sed hack (#3848)

configure.ac contains a sed line that cleans up incorrect library
flags which was added to paper over some bugs in earlier versions
of the Autotools. These issues are not a problem with the current
versions of the Autootols.

The sed line causes problems on MacOS, so it has been removed.

Fixes #3843

configure.ac

@@ -4285,11 +4285,5 @@ if test "X$HDF_FORTRAN" = "Xyes"; then
   esac
 fi
 
-## HDF5 configure code created by autotools with gcc 4.9.2 is adding problematic
-## linker flags:  -l with no library name; -l <libname>, specifically gfortran or m.
-## This sed script corrects "-l <libname>" first and then "-l " with no library name.
-## If the order is not preserved, all instances of "-l " will be removed.
-sed -e '/^postdeps/ s/-l \([a-zA-Z]\)/-l\1/g' -e '/^postdeps/ s/-l //g' -i libtool
-
 ## show the configure settings
 cat src/libhdf5.settings

release_docs/RELEASE.txt

@@ -835,6 +835,16 @@ Bug Fixes since HDF5-1.14.0 release
 
     Configuration
     -------------
+    - Removed an Autotools configure hack that causes problems on MacOS
+
+      A sed line in configure.ac was added in the past to paper over some
+      problems with older versions of the Autotools that would add incorrect
+      linker flags. This hack is not needed with recent versions of the
+      Autotools and the sed line errors on MacOS (though this was a silent
+      error that didn't break the build) so the hack has been removed.
+
+      Fixes GitHub issue #3843
+
     - Fixed an issue where the h5tools_test_utils test program was being
       installed on the system for Autotools builds of HDF5