qt4-mac link error lc++ not found

[kenneth.f.cunningham@…]

MacOSX 10.6.8, is setup using <​https://trac.macports.org/wiki/LibcxxOnOlderSystems>.

Installing qt4-mac fails with error -lc++ not found. Log attached.

Trying link manually, with verbose setting:

$ pwd
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_aqua_qt4-mac/qt4-mac/work/qt-everywhere-opensource-src-4.8.7/src/tools/moc
$ /opt/local/bin/clang++-mp-3.7 -v -L/opt/local/lib -Wl,-headerpad_max_install_names -stdlib=libc++ -arch x86_64 -Wl,-syslibroot,/Xcode3/SDKs/MacOSX10.6.sdk -Xarch_x86_64 -mmacosx-version-min=10.6 -Xarch_x86_64 -mmacosx-version-min=10.6 -o ../../../bin/moc release-shared/moc.o release-shared/preprocessor.o release-shared/generator.o release-shared/parser.o release-shared/token.o release-shared/main.o    -L/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_aqua_qt4-mac/qt4-mac/work/qt-everywhere-opensource-src-4.8.7/src/tools/bootstrap -lbootstrap -framework CoreServices -framework ApplicationServices -lz -lz
clang version 3.7.1 (tags/RELEASE_371/final)
Target: x86_64-apple-darwin10.8.0
Thread model: posix
 "/opt/local/libexec/llvm-3.7/bin/ld" -demangle -dynamic -arch x86_64 -macosx_version_min 10.6.0 -o ../../../bin/moc -lcrt1.10.6.o -L/opt/local/lib -L/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_aqua_qt4-mac/qt4-mac/work/qt-everywhere-opensource-src-4.8.7/src/tools/bootstrap -headerpad_max_install_names -syslibroot /Xcode3/SDKs/MacOSX10.6.sdk release-shared/moc.o release-shared/preprocessor.o release-shared/generator.o release-shared/parser.o release-shared/token.o release-shared/main.o -lbootstrap -framework CoreServices -framework ApplicationServices -lz -lz -lc++ -lSystem /opt/local/libexec/llvm-3.7/bin/../lib/clang/3.7.1/lib/darwin/libclang_rt.osx.a
ld: library not found for -lc++
clang: error: linker command failed with exit code 1 (use -v to see invocation)

libc++ is present in /usr/local, and other ports seem to install OK.

$ pwd
/usr/lib
$ ls -la libc*
-rwxr-xr-x  1 root  admin  1186580 12 Jan  2016 libc++.1.dylib
lrwxr-xr-x  1 root  admin       14 12 Jan  2016 libc++.dylib -> libc++.1.dylib
-rwxr-xr-x  1 root  admin   431040 24 Nov  2015 libc++abi.dylib
lrwxr-xr-x  1 root  wheel       15 25 Feb  2015 libc.dylib -> libSystem.dylib

might be related to this ticket <​https://trac.macports.org/ticket/50481> but seems different, as "-stdlib=libc++" seems to be present in the command line above.

My macports.conf relevant part:

# $Id: macports.conf.in 117120 2014-02-17 00:55:33Z jmr@macports.org $

cxx_stdlib         libc++
buildfromsource    always
delete_la_files    yes
default_compilers  macports-clang-3.7 macports-clang-3.4 macports-clang-3.3 gcc-4.2 apple-gcc-4.2 gcc-4.0
build_arch         x86_64

Thanks.