Cygwin下的gcc 9.3.0预处理器:cmdline -Dname，但名称似乎未定义

我正在尝试在Cygwin下构建OCRmyPDF，但遇到了一块砖头 墙。 虽然我的整个职业生涯都是开发人员，但我一直在工作 主要使用Java，对Python内部和C++知之甚少。 对于这些领域的专家来说，问题可能很明显，但我是 难倒。

Linux 上的 OCRmyPDF 作为一组"轮子"包安装。 我收集一个 wheel 是预先构建的依赖项捆绑包。 出于某种原因，在 Pip 安装人员 Cygwin 认为它不能使用车轮束并希望 从源重建。尝试重建 派克PDF包。

这是错误：

building 'pikepdf._qpdf' extension
creating build/temp.cygwin-3.1.4-x86_64-3.7
creating build/temp.cygwin-3.1.4-x86_64-3.7/src
creating build/temp.cygwin-3.1.4-x86_64-3.7/src/qpdf
gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -ggdb -O2 -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-strong --param=ssp-buffer-size=4 -fdebug-prefix-map=/cygdrive/d/cyg_pub/devel/python/python37/python37-3.7.7-1.x86_64/build=/usr/src/debug/python37-3.7.7-1 -fdebug-prefix-map=/cygdrive/d/cyg_pub/devel/python/python37/python37-3.7.7-1.x86_64/src/Python-3.7.7=/usr/src/debug/python37-3.7.7-1 -ggdb -O2 -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-strong --param=ssp-buffer-size=4 -fdebug-prefix-map=/cygdrive/d/cyg_pub/devel/python/python37/python37-3.7.7-1.x86_64/build=/usr/src/debug/python37-3.7.7-1 -fdebug-prefix-map=/cygdrive/d/cyg_pub/devel/python/python37/python37-3.7.7-1.x86_64/src/Python-3.7.7=/usr/src/debug/python37-3.7.7-1 -D__MISC_VISIBLE=1 -I/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include -I/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include -I/usr/include/python3.7m -c src/qpdf/annotation.cpp -o build/temp.cygwin-3.1.4-x86_64-3.7/src/qpdf/annotation.o -DVERSION_INFO="1.11.2" -std=c++14 -fvisibility=hidden
In file included from src/qpdf/annotation.cpp:18:
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h: In member function ‘void pybind11::cpp_function::initialize_generic(pybind11::detail::function_record*, const char*, const std::type_info* const*, pybind11::size_t)’:
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:197:21: error: ‘strdup’ was not declared in this scope; did you mean ‘strcmp’?
197 |         rec->name = strdup(rec->name ? rec->name : "");
|                     ^~~~~~
|                     strcmp
In file included from src/qpdf/annotation.cpp:18:
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h: In member function ‘pybind11::class_<type_, options>& pybind11::class_<type_, options>::def_property_static(const char*, const pybind11::cpp_function&, const pybind11::cpp_function&, const Extra& ...)’:
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1284:31: error: there are no arguments to ‘strdup’ that depend on a template parameter, so a declaration of ‘strdup’ must be available [-fpermissive]
1284 |               rec_fget->doc = strdup(rec_fget->doc);
|                               ^~~~~~
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1284:31: note: (if you use ‘-fpermissive’, G++ will accept your code, but allowing the use of an undeclared name is deprecated)
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1292:33: error: there are no arguments to ‘strdup’ that depend on a template parameter, so a declaration of ‘strdup’ must be available [-fpermissive]
1292 |                 rec_fset->doc = strdup(rec_fset->doc);
|                                 ^~~~~~
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h: In instantiation of ‘pybind11::class_<type_, options>& pybind11::class_<type_, options>::def_property_static(const char*, const pybind11::cpp_function&, const pybind11::cpp_function&, const Extra& ...) [with Extra = {pybind11::is_method, pybind11::return_value_policy}; type_ = QPDFAnnotationObjectHelper; options = {}]’:
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1263:80:   required from ‘pybind11::class_<type_, options>& pybind11::class_<type_, options>::def_property(const char*, const pybind11::cpp_function&, const pybind11::cpp_function&, const Extra& ...) [with Extra = {pybind11::return_value_policy}; type_ = QPDFAnnotationObjectHelper; options = {}]’
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1252:91:   required from ‘pybind11::class_<type_, options>& pybind11::class_<type_, options>::def_property(const char*, const Getter&, const Setter&, const Extra& ...) [with Getter = pybind11::cpp_function; Setter = std::nullptr_t; Extra = {pybind11::return_value_policy}; type_ = QPDFAnnotationObjectHelper; options = {}]’
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1234:58:   required from ‘pybind11::class_<type_, options>& pybind11::class_<type_, options>::def_property_readonly(const char*, const pybind11::cpp_function&, const Extra& ...) [with Extra = {pybind11::return_value_policy}; type_ = QPDFAnnotationObjectHelper; options = {}]’
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1228:87:   required from ‘pybind11::class_<type_, options>& pybind11::class_<type_, options>::def_property_readonly(const char*, const Getter&, const Extra& ...) [with Getter = std::basic_string<char> (QPDFAnnotationObjectHelper::*)(); Extra = {}; type_ = QPDFAnnotationObjectHelper; options = {}]’
src/qpdf/annotation.cpp:28:82:   required from here
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1284:37: error: ‘strdup’ was not declared in this scope; did you mean ‘strcmp’?
1284 |               rec_fget->doc = strdup(rec_fget->doc);
|                               ~~~~~~^~~~~~~~~~~~~~~
|                               strcmp
/tmp/pip-build-env-fdjj5aaz/overlay/lib/python3.7/site-packages/pybind11/include/pybind11/pybind11.h:1292:39: error: ‘strdup’ was not declared in this scope; did you mean ‘strcmp’?
1292 |                 rec_fset->doc = strdup(rec_fset->doc);
|                                 ~~~~~~^~~~~~~~~~~~~~~
|                                 strcmp
error: command 'gcc' failed with exit status 1
----------------------------------------
ERROR: Failed building wheel for pikepdf
Failed to build pikepdf
ERROR: Could not build wheels for pikepdf which use PEP 517 and cannot be installed directly

所以看起来pybind11.h需要strdup()但它不可用。strdup()在/usr/include/string.h中声明，其中包含 这：

#if __MISC_VISIBLE || __POSIX_VISIBLE >= 200809 || __XSI_VISIBLE >= 4
char    *strdup (const char *) __malloc_like __result_use_check;
#endif
char    *_strdup_r (struct _reent *, const char *);
#if __POSIX_VISIBLE >= 200809
char    *strndup (const char *, size_t) __malloc_like __result_use_check;
#endif

所以我尝试在命令行中添加显式-D__MISC_VISIBLE看看这是否可以解决问题，但它不起作用(如上所示(。 我捕获了 带有-E的预处理器输出，并发现即使使用-D__MISC_VISIBLE它的行为也好像没有定义该宏一样。仅显示_strdup_r：

Preprocessor output snippet
# 86 "/usr/include/string.h" 3 4
char *_strdup_r (struct _reent *, const char *);

这就是我卡住的地方。 我似乎无法制作编译器 包括strdup(). 我不确定下一步该如何进行，欢迎 任何建议。