fix: glog linking error when libunwind is present

[mrdrivingduck]

Purpose

When glog is built on systems with libunwind installed, it automatically detects and links against libunwind for stack unwinding support. However, the INTERFACE_LINK_LIBRARIES property was not set, causing undefined reference errors when linking static libraries:

/usr/bin/ld: ../../glog_ep-install/lib/libglog.a(stacktrace.cc.o): in function `google::glog_internal_namespace_::GetStackTrace(void**, int, int)':
stacktrace.cc:(.text+0x68): undefined reference to `_Ux86_64_getcontext'
/usr/bin/ld: stacktrace.cc:(.text+0x73): undefined reference to `_ULx86_64_init_local'
/usr/bin/ld: stacktrace.cc:(.text+0xa1): undefined reference to `_ULx86_64_get_reg'
/usr/bin/ld: stacktrace.cc:(.text+0xb4): undefined reference to `_ULx86_64_step'
/usr/bin/ld: stacktrace.cc:(.text+0xf7): undefined reference to `_ULx86_64_step'
collect2: error: ld returned 1 exit status

This change dynamically detects libunwind availability and adds it to glog's link interface only when present, ensuring portability across different build environments.

According to the docs of glog, libunwind is recommended.

Tests

For system without libunwind:

$ ldd ./usr/local/lib64/libpaimon.so 
        linux-vdso.so.1 (0x00007fff863ab000)
        libdl.so.2 => /lib64/libdl.so.2 (0x00007f0b897cf000)
        libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f0b87c10000)
        libm.so.6 => /lib64/libm.so.6 (0x00007f0b87aca000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f0b897b4000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f0b87aa8000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f0b878cc000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f0b897ee000)

For system with libunwind:

$ ldd ./usr/local/lib64/libpaimon.so
        linux-vdso.so.1 (0x00007ffcf1b3e000)
        libdl.so.2 => /lib64/libdl.so.2 (0x00007f52b4a12000)
        libunwind.so.8 => /lib64/libunwind.so.8 (0x00007f52b49f8000)
        libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f52b2e10000)
        libm.so.6 => /lib64/libm.so.6 (0x00007f52b2cca000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f52b49dd000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f52b49bb000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f52b2aee000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f52b4a31000)

API and Format

Documentation

[Copilot]

Pull request overview

This PR fixes linking errors that occur when glog is built on systems with libunwind installed. When libunwind is present, glog automatically links against it for stack unwinding support, but the INTERFACE_LINK_LIBRARIES property was not being set, causing undefined reference errors during static library linking.

Changes:

• Added dynamic detection of libunwind availability using CMake's find_library
• Conditionally adds libunwind to glog's interface link libraries when present
• Ensures portability across systems with and without libunwind

---

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[Copilot]

Consider using the variable ${LIBUNWIND_LIBRARY} instead of the bare library name "unwind". Since find_library stores the full path to the library in LIBUNWIND_LIBRARY, using ${LIBUNWIND_LIBRARY} ensures the exact library that was detected is linked. Alternatively, for better consistency with the codebase style at lines 474, 592, and 840, consider using target_link_libraries(glog INTERFACE ${LIBUNWIND_LIBRARY}) instead of set_property.

Suggested change

	set_property(TARGET glog
	APPEND
	PROPERTY INTERFACE_LINK_LIBRARIES unwind)
	endif()
	endmacro()
	target_link_libraries(glog INTERFACE ${LIBUNWIND_LIBRARY})
	endif()
	endmacro()
	endmacro()

[zjw1111]

+1

[mrdrivingduck]

Seems to be broken by main branch...

[zjw1111]

Seems to be broken by main branch...

Thanks to find this problem! It's caused by a random number case, we will fix this. cc @lxy-9602