444f64b3e9
autotools passes `LDFLAGS` automatically linker commands. curl's `lib/Makefile.am` customizes libcurl linker flags. In that customization, it added `LDFLAGS` to the custom flags. This resulted in passing `LDFLAGS` _twice_ to the `libtool` command. Most of the time this is benign, but some `LDFLAGS` options can break the build when passed twice. One such example is passing `.o` files, e.g. `crt*.o` files necessary when customizing the C runtime, e.g. for MUSL builds. Passing them twice resulted in duplicate symbol errors: ``` libtool: link: clang-15 --target=aarch64-unknown-linux-musl [...] /usr/lib/aarch64-linux-musl/crt1.o [...] /usr/lib/aarch64-linux-musl/crt1.o [...] ld.lld-15: error: duplicate symbol: _start >>> defined at crt1.c >>> /usr/lib/aarch64-linux-musl/crt1.o:(.text+0x0) >>> defined at crt1.c >>> /usr/lib/aarch64-linux-musl/crt1.o:(.text+0x0) [...] clang: error: linker command failed with exit code 1 (use -v to see invocation) ``` This behaviour came with commit 1a593191c2769a47b8c3e4d9715ec9f6dddf5e36 (2013-07-23) as a fix for bug https://curl.haxx.se/bug/view.cgi?id=1217. The patch was a works-for-me hack that ended up merged in curl: https://sourceforge.net/p/curl/bugs/1217/#06ef With the root cause remaining unclear. Perhaps the SUNPro 12 linker was sensitive to `-L` `-l` order, requiring `-L` first? This would be unusual and suggests a bug in either the linker or in `libtool`. The curl build does pass the list of detected libs via its own `LIBCURL_LIBS` variable, which ends up before `LDFLAGS` on the `libtool` command line, but it's the job of `libtool` to ensure that even a peculiar linker gets the options in the expected order. Also because autotools passes `LDFLAGS` last, making it hardly possible to pass anything after it. Perhaps in the 10 years since this issue, this already got a fix upstream. This patch deletes `LDFLAGS` from our customized libcurl options, leaving a single copy of them as passed by autotools automatically. Reverts 1a593191c2769a47b8c3e4d9715ec9f6dddf5e36 Closes #12310
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