[MacPorts] #56511: gcc49 @4.9.4_2: rev-upgrade rebuild fails on macOS 10.12.6 XCode 9.2

[MacPorts]

#56511: gcc49 @4.9.4_2: rev-upgrade rebuild fails on macOS 10.12.6 XCode 9.2
----------------------+--------------------
 Reporter:  mopihopi  |      Owner:  (none)
     Type:  defect    |     Status:  new
 Priority:  Normal    |  Milestone:
Component:  ports     |    Version:
 Keywords:            |       Port:  gcc49
----------------------+--------------------
 The recent mpfr update causes the gcc49 binary to break (libmpfr.4.dylib →
 libmpfr.6.dylib), so rev-upgrade attempts to rebuild it.  However the
 rebuild fails, on macOS 10.12.6 with XCode 9.2:

 {{{
 --->  Scanning binaries for linking errors
 --->  Found 7 broken files, matching files to ports
 --->  Found 1 broken port, determining rebuild order
 You can always run 'port rev-upgrade' again to fix errors.
 The following ports will be rebuilt: gcc49 @4.9.4
 Continue? [Y/n]: y
 --->  Computing dependencies for gcc49
 --->  Cleaning gcc49
 --->  Scanning binaries for linking errors
 --->  Found 7 broken files, matching files to ports
 --->  Found 1 broken port, determining rebuild order
 --->  Rebuilding in order
      gcc49 @4.9.4
 --->  Computing dependencies for gcc49
 --->  Fetching distfiles for gcc49
 --->  Attempting to fetch gcc-4.9.4.tar.bz2 from
 https://distfiles.macports.org/gcc49
 --->  Verifying checksums for gcc49
 --->  Extracting gcc49
 --->  Applying patches to gcc49
 --->  Configuring gcc49
 --->  Building gcc49
 Error: Failed to build gcc49: command execution failed
 Error: See
 /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_lang_gcc49/gcc49/main.log
 for details.
 Error: rev-upgrade failed: Error rebuilding gcc49
 Error: Follow https://guide.macports.org/#project.tickets to report a bug.
 }}}

 main.log contains the following compiler error:
 {{{
 ...
 :info:build In file included from
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/new:89:
 :info:build
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/exception:173:5:
 error: no member named 'fancy_abort' in namespace 'std::__1'; did you mean
 simply 'fancy_abort'?
 ...
 }}}

 {{{
 $ sw_vers
 ProductName:    Mac OS X
 ProductVersion: 10.12.6
 BuildVersion:   16G1314
 $ xcodebuild -version
 Xcode 9.2
 Build version 9C40b
 $
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/56511>
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