将 Mac OSX 10.8 上的 GraphicsMagick 与 clang 和 libc++ 链接起来

在过去的几天里，我一直在尝试将GraphicsMagick纳入我的项目中，但没有运气，希望这里有人可以帮助我（如果这太长，请参阅最后的TL/DR）。

由于我需要JPEG，PNG和lcms支持，我之前使用配置和制作工具下载并构建了它们：

./configure CC=clang
make
sudo make install

所有这些似乎都工作正常，所以下载 GraphicsMagick 后，我再次运行配置：

CC=clang CXX="clang++ -stdlib=libc++" CXXFLAGS="-stdlib=libc++" LDFLAGS="-stdlib=libc++" ./configure --enable-shared --disable-static --disable-openmp --without-xml --without-zlib --without-bzlib

然后make创建我的动态库：libGraphicsMagick.3.dylib和libGraphicsMagick++.3.dylib。当我使用 MacDependency 或 otool 检查 libGraphicsMagick++ 时，我看到它链接到/usr/lib/libc++.1.dylib（而不是 libstdc++）

创建一个新项目，请添加#include <Magick++.h>（由上一步在/usr/local/include/GraphicsMagick 中安装），只是这样，实际上没有使用任何功能，我会收到链接错误：

clang++ -headerpad_max_install_names -stdlib=libc++ -arch x86_64 -o TestMagickApp.app/Contents/MacOS/TestMagickApp main.o widget.o moc_widget.o   -F/Library/Frameworks -L/Library/Frameworks -framework QtGui -framework QtCore 
Undefined symbols for architecture x86_64:
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::gptr() const", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::underflow() in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::pbackfail(int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::pptr() const", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::underflow() in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::pbackfail(int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::eback() const", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::underflow() in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::pbackfail(int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::egptr() const", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::underflow() in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::epptr() const", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::pbase() const", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
  "std::__1::basic_iostream<char, std::__1::char_traits<char> >::basic_iostream(std::__1::basic_streambuf<char, std::__1::char_traits<char> >*)", referenced from:
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_stringstream(unsigned int) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::setg(char*, char*, char*)", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::underflow() in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::pbackfail(int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::str(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::setp(char*, char*)", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::str(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::pbump(int)", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::seekoff(long long, std::__1::ios_base::seekdir, unsigned int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::str(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in widget.o
  "std::__1::basic_streambuf<char, std::__1::char_traits<char> >::sputc(char)", referenced from:
      std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char> >::overflow(int) in widget.o
  "std::__1::basic_ios<char, std::__1::char_traits<char> >::basic_ios()", referenced from:
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_stringstream(unsigned int) in widget.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [TestMagickApp.app/Contents/MacOS/TestMagickApp] Error 1
19:43:22: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project TestMagickApp (kit: 4.8.5)
When executing step 'Make'

但这只发生在我尝试使用 libc++ 时，如果我尝试使用 libstdc++ 代替，它会毫无问题地链接（但如果我仍然在思考，一旦我尝试使用任何功能，它就会出错）。

我尝试仅包含某些文件以缩小问题范围，似乎它是由/usr/local/include/GraphicsMagick/magick/common.h中的这段代码引起的：

/*
  Support for __attribute__ was added in GCC 2.0.  It is not supported
  in strict ANSI mode which is indicated by __STRICT_ANSI__ being
  defined.
  http://www.ohse.de/uwe/articles/gcc-attributes.html
  Note that GCC 3.2 on MinGW does not define __GNUC__ or __GNUC_MINOR__.
*/
#if !defined(__attribute__)
#  if (!defined(__GNUC__) || (__GNUC__ < 2 || __STRICT_ANSI__))
#    define __attribute__(x) /*nothing*/
#  else
#    if (((__GNUC__) > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1))) /* 3.1+ */
#      define MAGICK_FUNC_DEPRECATED __attribute__((__deprecated__))
#    endif
#    if (__GNUC__ >= 3)  /* 3.0+ */
#      define MAGICK_FUNC_MALLOC __attribute__((__malloc__))
#    endif
#    if (((__GNUC__) > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)))  /* 3.3+ */
  /* Supports argument syntax like __attribute__((nonnull (1, 2))) but
     don't know how to support non-GCC fallback. */
#      define MAGICK_FUNC_NONNULL __attribute__((__nonnull__))
#    endif
#    if (((__GNUC__) > 3) || ((__GNUC__ == 2) && (__GNUC_MINOR__ >= 5))) /* 2.5+ */
#      define MAGICK_FUNC_NORETURN __attribute__((__noreturn__))
#    endif
#    if ((__GNUC__) >= 3) /* 2.96+ */
#      define MAGICK_FUNC_PURE __attribute__((__pure__))
#    endif
#    if (((__GNUC__) > 3) || ((__GNUC__ == 2) && (__GNUC_MINOR__ >= 7))) /* 2.7+ */
#      define MAGICK_FUNC_UNUSED __attribute__((__unused__))
#    endif
#    if (((__GNUC__) > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)))  /* 3.3+ */
#      define MAGICK_FUNC_WARN_UNUSED_RESULT __attribute__((__warn_unused_result__))
#    endif
#    if (((__GNUC__) > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)))  /* 4.3+ */
#      define MAGICK_FUNC_ALLOC_SIZE_1ARG(arg_num) __attribute__((__alloc_size__(arg_num)))
#      define MAGICK_FUNC_ALLOC_SIZE_2ARG(arg_num1,arg_num2) __attribute__((__alloc_size__(arg_num1,arg_num2)))
#      define MAGICK_FUNC_HOT __attribute__((__hot__))
#      define MAGICK_FUNC_COLD __attribute__((__cold__))
#      define MAGICK_OPTIMIZE_FUNC(opt) __attribute__((__optimize__ (opt)))
#    endif
#    if (((__GNUC__) > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)))  /* 4.7+ */
#      define MAGICK_ASSUME_ALIGNED(exp,align) __builtin_assume_aligned(exp,align)
#      define MAGICK_ASSUME_ALIGNED_OFFSET(exp,align,offset) __builtin_assume_aligned(exp,align,offset)
#    endif
#  endif
#endif

现在我不太理解这段代码，但它似乎支持非常旧的编译器（GCC 版本 <2！！如果我注释掉整个部分，它似乎编译得很好，但由于我不知道它在做什么，注释掉它感觉有点风险/奇怪，因为它是一个只读文件，它有点表明我不应该真的搞砸它无论如何我猜

值得一提的是，使用GraphicsMagick的应用程序也使用Qt 4.8.5，我正在使用QtCreator和QMake，但我认为它在这里无关紧要。我也尝试过Qt 5.1和5.2，但没有运气。

clang++ --version返回Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)（我知道它不是最新版本，但我宁愿不更改它）。

TL/DR：

有没有人对使用 libc++ 编译 GraphicsMagick 有任何经验/反馈？

有人可以向我解释上面的最后一段代码在做什么吗？为什么当我注释掉它时它会起作用？

你能发现我所做的事情有什么不对吗？整个过程我做了几次，但也许我忘记了一些明显的东西......

任何帮助将非常受欢迎。