make: avoid strlcpy/strlcat redefinition on glibc 2.38+ #136
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7580913 failed because |
Newer glibc (≥ 2.38) provides built-in implementations of strlcpy() and strlcat(). Projects that also define these functions will now fail to build due to symbol redefinition conflicts. This patch is trying to verify whether strlcpy()/strlcat() are available at compile time and only compiles the compatibility implementation when missing. (e.g. glibc is older 2.38) This commit also revert 7580913. Because __has_builtin() only checks for functions built in the compiler(*), as listed in [2]. It never checks again glibc or other libraries. In GCC, only some standard C functions have compiler built-in version. Nonstandard C library functions (here strlcpy() and strlcat()) do not have compiler built-in version. [1]: https://sourceware.org/git/?p=glibc.git;a=commit;h=454a20c8756c9c1d55419153255fc7692b3d2199 [2]: https://gcc.gnu.org/onlinedocs/gcc/Built-in-Functions.html * Thanks to "Wei-Cheng Yeh (IID)" <iid@ccns.ncku.edu.tw> for helping confirm the root cause.
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Newer glibc (≥ 2.38) provides built-in implementations of strlcpy() and strlcat(). Projects that also define these functions will now fail to build due to symbol redefinition conflicts.
This patch is trying to verify whether strlcpy()/strlcat() are available at compile time and only compiles the compatibility implementation when missing. (e.g. glibc is older 2.38)
ref: https://sourceware.org/git/?p=glibc.git;a=commit;h=454a20c8756c9c1d55419153255fc7692b3d2199
related previous discussion: #135
related build test: https://github.com/bbsdocker/imageptt/actions/runs/19000701482