为什么在我的系统上的 ld 搜索路径中添加了一个额外的“../”？

Question

#include <iostream>

using namespace std;

int main() {
    cout << "Hello\n";
    return 0;
}

如果我在我的 Ubuntu 18.04 系统上编译上面的程序，

$ g++ hello.cpp -o hello
/usr/bin/ld: cannot find crtbeginS.o: No such file or directory
/usr/bin/ld: cannot find -lstdc++
collect2: error: ld returned 1 exit status

我的系统上有gcc 7.4和ld 2.30 。 如果我列出系统上的搜索路径：

$ ldconfig -v 2>/dev/null | grep -v ^$'\t'
/usr/lib/x86_64-linux-gnu/libfakeroot:
/lib/i386-linux-gnu:
/usr/lib/i386-linux-gnu:
/usr/local/lib:
/lib/x86_64-linux-gnu:
/usr/lib/x86_64-linux-gnu:
/lib32:
/usr/lib32:
/libx32:
/usr/libx32:
/lib:
/usr/lib:
/usr/lib/i386-linux-gnu/sse2: (hwcap: 0x0000000000000001)

$ strace g++ hello.cpp -o hello 2>&1 | grep crtbeginS.o
access("/lib/gcc/x86_64-linux-gnu/7/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/../x86_64-linux-gnu/lib/x86_64-linux-gnu/7/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/../x86_64-linux-gnu/lib/x86_64-linux-gnu/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/../x86_64-linux-gnu/lib/../lib/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/7/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/gcc/x86_64-linux-gnu/7/../../../../lib/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/x86_64-linux-gnu/7/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/x86_64-linux-gnu/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/../lib/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/x86_64-linux-gnu/7/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/x86_64-linux-gnu/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/../lib/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/../x86_64-linux-gnu/lib/crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/gcc/x86_64-linux-gnu/7/../../../crtbeginS.o", R_OK) = -1 ENOENT (No such file or directory)
access("/lib/crtbeginS.o", R_OK)        = -1 ENOENT (No such file or directory)
access("/usr/lib/crtbeginS.o", R_OK)    = -1 ENOENT (No such file or directory)
wait4(19085, /usr/bin/ld: cannot find crtbeginS.o: No such file or directory

有趣的是：

$ ll /usr/lib/gcc/x86_64-linux-gnu/7/crtbeginS.o
-rw-r--r-- 1 root root 2.8K May  8  2019 /usr/lib/gcc/x86_64-linux-gnu/7/crtbeginS.o

但是，如果您注意到/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/7/crtbeginS.o在上面免费添加了三个../ .

把问题说清楚； 为什么在我的系统上的 ld 搜索路径中添加了额外的“../”？