libxml2 fails to build on 10.13.4

[andregirard]

libxml2 fails to build after the following sequence of operations. Xcode is version 9.3.1

sudo port selfupdate
--->  Updating MacPorts base sources using rsync
MacPorts base version 2.6.2 installed,
MacPorts base version 2.6.2 downloaded.
--->  Updating the ports tree
--->  MacPorts base is already the latest version

sudo port clean libxml2
--->  Cleaning libxml2

sudo port upgrade outdated
--->  Computing dependencies for libxml2
--->  Fetching archive for libxml2
--->  Attempting to fetch libxml2-2.9.9_3+universal.darwin_17.i386-x86_64.tbz2 from https://packages.macports.org/libxml2
--->  Attempting to fetch libxml2-2.9.9_3+universal.darwin_17.i386-x86_64.tbz2 from http://ywg.ca.packages.macports.org/mirror/macports/packages/libxml2
--->  Attempting to fetch libxml2-2.9.9_3+universal.darwin_17.i386-x86_64.tbz2 from http://aus.us.packages.macports.org/macports/packages/libxml2
--->  Fetching distfiles for libxml2
--->  Verifying checksums for libxml2
--->  Extracting libxml2
--->  Applying patches to libxml2
--->  Configuring libxml2
Error: Failed to configure libxml2, consult /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_libxml2/libxml2/work/libxml2-2.9.9/config.log
Error: Failed to configure libxml2: configure failure: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_libxml2/libxml2/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.

[mf2k (Frank Schima)]

Error is:

:info:configure dyld: Library not loaded: /opt/local/lib/libreadline.7.dylib
:info:configure   Referenced from: /opt/local/bin/gawk
:info:configure   Reason: image not found

[mf2k (Frank Schima)]

Duplicate of #57955. gawk needs to be upgraded.