Qt开源版交叉编译gmake阶段失败求助

正在交叉编译Qt开源版本，configure命令执行正常，但执行gmake时，qtbase/src/3rdparty/pcre2模块出现编译失败。确认已包含pthread.h且该头文件定义了PTHREAD_MUTEX_INITIALIZER宏，同时sys/mman.h文件也存在于指定sysroot路径中，且其他子项目编译正常，求修复建议。

编译报错信息 #

gmake[3]: Entering directory '/root/raspi/qt-build/qtbase/src/3rdparty/pcre2'
/root/raspi/arm-gnu-toolchain-12.2.mpacbti-rel1-x86_64-arm-none-eabi/bin/arm-none-eabi-gcc -c -march=armv8-a -mtune=cortex-a53 -mfpu=crypto-neon-fp-armv8 --sysroot=/root/raspi/sysroot -O2 -fPIC -std=gnu11 -fvisibility=hidden -w -fno-exceptions -DQT_NO_LINKED_LIST -DQT_NO_JAVA_STYLE_ITERATORS -DPCRE2_CODE_UNIT_WIDTH=16 -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DHAVE_CONFIG_H -DQT_NO_DYNAMIC_CAST -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -I/root/raspi/qt-everywhere-src-5.15.9/qtbase/src/3rdparty/pcre2 -I. -I/root/raspi/qt-everywhere-src-5.15.9/qtbase/src/3rdparty/pcre2/src -I/root/raspi/qt-everywhere-src-5.15.9/qtbase/mkspecs/devices/linux-rasp-pi3-g++ -o .obj/pcre2_jit_compile.o /root/raspi/qt-everywhere-src-5.15.9/qtbase/src/3rdparty/pcre2/src/pcre2_jit_compile.c
In file included from /root/raspi/qt-everywhere-src-5.15.9/qtbase/src/3rdparty/pcre2/src/sljit/sljitLir.c:260,
                 from /root/raspi/qt-everywhere-src-5.15.9/qtbase/src/3rdparty/pcre2/src/pcre2_jit_compile.c:79:
/root/raspi/qt-everywhere-src-5.15.9/qtbase/src/3rdparty/pcre2/src/sljit/sljitUtils.c:41:41: error: 'PTHREAD_MUTEX_INITIALIZER' undeclared here (not in a function)
   41 | static pthread_mutex_t allocator_lock = PTHREAD_MUTEX_INITIALIZER;
      |                                         ^~~~~~~~~~~~~~~~~~~~~~~~~
/root/raspi/qt-everywhere-src-5.15.9/qtbase/src/3rdparty/pcre2/src/sljit/sljitUtils.c:77:10: fatal error: sys/mman.h: No such file or directory
   77 | #include <sys/mman.h>

引发第一个错误的源文件片段 #

#include <pthread.h>
static pthread_mutex_t allocator_lock = PTHREAD_MUTEX_INITIALIZER;

相关头文件的实际位置 #

[root@fedora qt-build]# find /root/raspi -name mman.h | grep sys
/root/raspi/sysroot/usr/include/aarch64-linux-gnu/asm/mman.h
/root/raspi/sysroot/usr/include/aarch64-linux-gnu/bits/mman.h
/root/raspi/sysroot/usr/include/aarch64-linux-gnu/sys/mman.h
/root/raspi/sysroot/usr/include/asm-generic/mman.h
/root/raspi/sysroot/usr/include/linux/mman.h
/root/raspi/qt-everywhere-src-5.15.9/qtwebengine/src/3rdparty/chromium/third_party/crashpad/crashpad/compat/android/sys/mman.h
/root/raspi/qt-everywhere-src-5.15.9/qtwebengine/src/3rdparty/chromium/third_party/crashpad/crashpad/compat/linux/sys/mman.h
[root@fedora qt-build]# find /root/raspi -name pthread.h
/root/raspi/sysroot/usr/include/pthread.h
/root/raspi/arm-gnu-toolchain-12.2.mpacbti-rel1-x86_64-arm-none-eabi/arm-none-eabi/include/pthread.h

修复建议 #

1. 补全pthread宏定义 #

PTHREAD_MUTEX_INITIALIZER需要在定义_POSIX_C_SOURCE（值≥199506L）或_GNU_SOURCE宏后才会被pthread.h暴露。可以：

• 重新执行configure时添加编译参数：-extra-cflags="-D_POSIX_C_SOURCE=199506L"
• 或者直接修改sljitUtils.c，在包含pthread.h前添加宏：

  #define _POSIX_C_SOURCE 199506L
  #include <pthread.h>
  

2. 修复sys/mman.h路径识别 #

从文件位置看，sys/mman.h在aarch64-linux-gnu子目录下，交叉编译器可能未自动搜索该路径：

• 手动创建软链接，让编译器能直接找到：

  ln -s /root/raspi/sysroot/usr/include/aarch64-linux-gnu/sys/mman.h /root/raspi/sysroot/usr/include/sys/mman.h
  

• 或者在configure时添加额外包含路径：-extra-cflags="-I/root/raspi/sysroot/usr/include/aarch64-linux-gnu"

3. 禁用pcre2的JIT编译 #

如果上述方法无效，可直接跳过JIT相关代码编译：

• 重新configure时添加参数：-no-pcre-jit

4. 检查工具链与sysroot的匹配性 #

你使用的arm-none-eabi-gcc通常用于裸机开发，而sysroot是针对aarch64-linux-gnu的树莓派3（64位），存在架构工具链不匹配问题。更换为aarch64-linux-gnu-gcc工具链后，重新执行configure和编译。

内容的提问来源于stack exchange，提问作者TSG