使用pyenv安装python时，waf check_python_headers失败。

Question

我正在尝试使用waf生成工具构建一个项目。当检查python头时，构建在配置步骤中失败。

我将问题缩小到了我的wscript的最小示例：

def options(ctx):
        ctx.load('compiler_c')

def configure(ctx):
    ctx.load('compiler_c python')
    ctx.check_python_version((2,7,0))
    if int(ctx.env.PYTHON_VERSION[0]) == 2:
        print ('→ Configuring for python2')
    else:
        print ('→ Configuring for python3')
    ctx.check_python_headers(features='pyext')

我使用我在Ubuntu20.04上与碧昂夫一起安装的python版本(3.6.12和3.7.9)。

我以这样的方式运行它，但是它失败了，我无法理解它的错误：

$ python waf configure
Setting top to                           : /home/myuser/waf-test
Setting out to                           : /home/myuser/waf-test/build
Checking for 'gcc' (C compiler)          : /usr/bin/gcc
Checking for program 'python'            : /home/myuser/.pyenv/versions/3.7.9/bin/python
Checking for python version >= 2.7.0     : 3.7.9
→ Configuring for python3
python-config                            : /home/myuser/.pyenv/versions/3.7.9/bin/python-config
Asking python-config for pyext '--cflags --libs --ldflags' flags : yes
Testing pyext configuration                                      : Could not build python extensions
The configuration failed
(complete log in /home/myuser/waf-test/build/config.log)

$ tail -n 20 build/config.log
[1/2] Compiling build/.conf_check_d3b505aa7ab58576b6d76a2fc3091b1f/test.c
['/usr/bin/gcc', '-fPIC', '-g', '-fwrapv', '-O3', '-I../../../../.pyenv/versions/3.7.9/include/python3.7m', '-DPYTHONDIR="/usr/local/lib/python3.7/site-packages"', '-DPYTHONARCHDIR="/usr/local/lib/python3.7/site-packages"', '-DNDEBUG', '../test.c', '-c', '-o/home/myuser/waf-test/build/.conf_check_d3b505aa7ab58576b6d76a2fc3091b1f/testbuild/test.c.1.o']
[2/2] Linking build/.conf_check_d3b505aa7ab58576b6d76a2fc3091b1f/testbuild/testprog.cpython-37m-x86_64-linux-gnu.so
['/usr/bin/gcc', '-shared', 'test.c.1.o', '-o/home/myuser/waf-test/build/.conf_check_d3b505aa7ab58576b6d76a2fc3091b1f/testbuild/testprog.cpython-37m-x86_64-linux-gnu.so', '-Wl,-Bstatic', '-Wl,-Bdynamic', '-L/home/myuser/.pyenv/versions/3.7.9/lib/python3.7/config-3.7m-x86_64-linux-gnu', '-L/home/myuser/.pyenv/versions/3.7.9/lib', '-lpython3.7m', '-lcrypt', '-lpthread', '-ldl', '-lutil', '-lm', '-lpython3.7m', '-lcrypt', '-lpthread', '-ldl', '-lutil', '-lm']
err: /usr/bin/ld: /home/myuser/.pyenv/versions/3.7.9/lib/python3.7/config-3.7m-x86_64-linux-gnu/libpython3.7m.a(pylifecycle.o): relocation R_X86_64_PC32 against symbol `Py_VerboseFlag' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status
from /home/myuser/waf-test: Test does not build: Traceback (most recent call last):
  File "/home/myuser/waf-test/.waf3-2.0.20-36f5354d605298f6a89c09e0c7ef6c1d/waflib/Configure.py", line 335, in run_build
    bld.compile()
  File "/home/myuser/waf-test/.waf3-2.0.20-36f5354d605298f6a89c09e0c7ef6c1d/waflib/Build.py", line 176, in compile
    raise Errors.BuildError(self.producer.error)
waflib.Errors.BuildError: Build failed
 -> task in 'testprog' failed with exit status 1 (run with -v to display more information)
Could not build python extensions
from /home/myuser/waf-test: The configuration failed

请注意，python 3.8.6也安装在pyenv中，没有出现此问题。我可以配置没有错误。

My的问题：为什么在pyenv中的python在一个版本中检查失败，而在另一个版本中检查失败呢？因为我只是用pyenv install 3.6.12安装版本，所以我需要在安装中更改什么才能使我的构建成功？

Answer 1

错误在于，在创建测试程序以检查pyext是否正确设置时，编译器抱怨libpython3.7m.a中包含的pylifecycle.o是不可重定位的，即不使用-fPIC标志编译。

由于waf生成的代码片段是用-fPIC编译的，所以问题似乎是libpython3.7m.a中的pylifecycle.o不是用-fPIC编译的，这在静态库中是有意义的。也许问题在于它使用的是.a存档库，而不是共享对象，即.so。

检查您是否有libpython libpython3.7m.so的共享对象版本。