OS X 编译错误：ld：找不到 x86_64 架构的符号

Question

在这里编译的新手，请耐心等待。我正在尝试在 OS X 10.10.3 上使用make. 我安装了 XCode 6.3.1。我的 Makefile 是使用 qmake 生成的。编译器运行良好，直到它尝试运行最终构建命令并抛出错误：

Undefined symbols for architecture x86_64:
  "_iconv", referenced from:
      puntoexe::charsetConversionIconv::myIconv(void*, char*, unsigned long) const in charsetConversionIconv.o
  "_iconv_close", referenced from:
      puntoexe::charsetConversionIconv::close() in charsetConversionIconv.o
  "_iconv_open", referenced from:
      puntoexe::charsetConversionIconv::initialize(int) in charsetConversionIconv.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: *** [dicom2jpeg.app/Contents/MacOS/dicom2jpeg] Error 1

我在这里发现多个线程描述了一个类似的问题，显然它归结为链接到 32 位库的编译器。对其他人有效的主要建议是将以下代码添加到 Makefile 中：

-stdlib=libstdc++

qmake 生成的 Makefile 如下所示：

CC            = clang
CXX           = clang++
DEFINES       = -DQT_NO_DEBUG
CFLAGS        = -pipe -mmacosx-version-min=10.7 -O2 -arch x86_64 -Wall -W $(DEFINES)
CXXFLAGS      = -pipe -stdlib=libc++ -mmacosx-version-min=10.7 -O2 -arch x86_64 -Wall -W $(DEFINES)
INCPATH       = -I/usr/local/Cellar/qt/4.8.6/mkspecs/unsupported/macx-clang-libc++ -I. -I/usr/local/Cellar/qt/4.8.6/include -I.
LINK          = clang++
LFLAGS        = -headerpad_max_install_names -stdlib=libc++ -mmacosx-version-min=10.7 -arch x86_64
LIBS          = $(SUBLIBS)  -L/usr/local/Cellar/qt/4.8.6/lib -lpthread

因此，我已更改我的 Makefile 以链接到相应的库：

CC            = clang
CXX           = clang++
DEFINES       = -DQT_NO_DEBUG
CFLAGS        = -pipe -mmacosx-version-min=10.7 -O2 -arch x86_64 -Wall -W $(DEFINES)
CXXFLAGS      = -pipe -stdlib=libstdc++ -mmacosx-version-min=10.7 -O2 -arch x86_64 -Wall -W $(DEFINES)
INCPATH       = -I/usr/local/Cellar/qt/4.8.6/mkspecs/unsupported/macx-clang-libc++ -I. -I/usr/local/Cellar/qt/4.8.6/include -I.
LINK          = clang++
LFLAGS        = -headerpad_max_install_names -stdlib=libstdc++ -mmacosx-version-min=10.7 -arch x86_64
LIBS          = $(SUBLIBS)  -L/usr/local/Cellar/qt/4.8.6/lib -lpthread

但是，没有骰子。在最终构建时仍然抛出相同的错误。我错过了什么吗？