Bug#736991: libc++: FTBFS on various architectures

[Andreas Beckmann]

Source: libc++
Version: 1.0~svn199600-1
Severity: serious
Justification: fails to build from source

Hi,

libc++ FTBFS on most architectures, including armel/armhf where it
previously built successfully.
https://buildd.debian.org/status/package.php?p=libc%2b%2b

>From the armel buildlog:

[...]
cd libcxx/lib; ./buildit; ln -s libc++.so.1.0 libc++.so;\
	ln -s libc++.so.1.0 libc++.so.1;
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/algorithm.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/bind.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/chrono.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/condition_variable.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/debug.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/exception.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/future.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/hash.cpp
+ clang++ -c -g -Os -fPIC -nostdinc++ -std=c++11 -fstrict-aliasing -Wall -Wextra -Wshadow -Wconversion -Wpadded -Wstrict-aliasing=2 -Wstrict-overflow=4 -DLIBCXXABI -I../include -I../../libcxxabi/include ../src/ios.cpp
In file included from ../src/ios.cpp:12:
In file included from ../include/ios:216:
In file included from ../include/__locale:15:
In file included from ../include/string:439:
In file included from ../include/algorithm:627:
In file included from ../include/memory:610:
.../include/atomic:662:17: error: cannot compile this atomic library call yet
        {return __c11_atomic_fetch_add(&this->__a_, __op, __m);}
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[1]: Leaving directory `/build/libc++-0S_Ol2/libc++-1.0~svn199600'
   dh_auto_test -a
 fakeroot debian/rules binary-arch
dh binary-arch
   dh_testroot -a
   dh_prep -a
   dh_installdirs -a
   dh_auto_install -a
   dh_install -a
dh_install: libc++-dev missing files (libcxx/lib/*.a), aborting
make: *** [binary-arch] Error 2


The buildsystem seems broken since the build failure gets ignored.
Probably builtit.sh is missing a 'set -e' like is the multi-command in
the rules file. That should start with

  set -e ; cd somewhere ; ./doit ; ./domore


Andreas