In its default configuration, pkg-config adds system-wide library
directories to the linker search path (rust-lang/pkg-config-rs#11).
This causes these directories to be searched before other paths added
by later crates or by -Clink-arg in rustflags. If a library is present in
the system-wide directory and a later build step wants to specifically
link against a different version of that library in another path, the linker
will choose the library from the first search directory it finds. If the linker
doesn't find a library in any of the specified search directories, it falls
back on system-wide paths, so we don't need to print the
path we found lubcurl in if it is in one of those system paths.
See rust-lang/libz-sys#50 for the same fix to libz that landed a while back.
In its default configuration, pkg-config adds system-wide library directories to the linker search path (rust-lang/pkg-config-rs#11). This causes these directories to be searched before other paths added by later crates or by
-Clink-argin rustflags. If a library is present in the system-wide directory and a later build step wants to specifically link against a different version of that library in another path, the linker will choose the library from the first search directory it finds. If the linker doesn't find a library in any of the specified search directories, it falls back on system-wide paths, so we don't need to print the path we found lubcurl in if it is in one of those system paths.See rust-lang/libz-sys#50 for the same fix to libz that landed a while back.