Ubuntu – Why 'constructor' attributed function with the same name is called 3 times from library X instead of 1 time from libraries X, Y, Z

Scenario:

$ cat lib.c
#include <stdio.h>
#define STR_(x) #x
#define STR(x) STR_(x)
#define CAT_(x,y) x##y
#define CAT(x,y) CAT_(x,y)

__attribute__((constructor))
void CAT(foo,)(void) { printf("foo" STR(N) " %pn", CAT(foo,)); }
void CAT(bar,N)(void){ puts("bar" STR(N)); }

$ cat main.c
void barx(void);
void bary(void);
void barz(void);

int main(void)
{
    barx();
    bary();
    barz();
}

$ cat build_run.sh
gcc lib.c -DN=x -c -fPIC -o libx.o && gcc libx.o -o libx.so -shared &&
gcc lib.c -DN=y -c -fPIC -o liby.o && gcc liby.o -o liby.so -shared &&
gcc lib.c -DN=z -c -fPIC -o libz.o && gcc libz.o -o libz.so -shared &&
export LD_LIBRARY_PATH=.:$LD_LIBRARY_PATH &&
gcc -L. -o main main.c -lx -ly -lz &&
./main

$ bash build_run.sh
foox 0x7f0bf002e139
foox 0x7f0bf002e139
foox 0x7f0bf002e139
barx
bary
barz

Here we see that:

1. All .so libraries have constructor attributed function with the same name foo.
2. Function foo is called 3 times from library X (which may be unexpected behavior) instead of 1 time from libraries X, Y, Z (which may be expected behavior).

As I understand, addresses of constructor attributed functions foo are placed (directly or indirectly) in .init_array section. Hence, function names are expected to be irrelevant.

The core question: why function foo is called 3 times from library X instead of 1 time from libraries X, Y, Z?

Extra observations:

1. If we change in lib.c from CAT(foo,) to CAT(foo,N) and rerun the build_run.sh, then we will see:

$ bash build_run.sh
fooz 0x7fc121dcc139
fooy 0x7fc121dd1139
foox 0x7fc121dd6139
barx
bary
barz

which is expected behavior.

2. Running the original (i.e. with CAT(foo,)) example on Cygwin leads to function foo is called 1 time from libraries X, Y, Z (which may be expected behavior).

System and software info:

$ uname -a
Linux xxx 5.15.0-79-generic #86-Ubuntu SMP Mon Jul 10 16:07:21 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

$ gcc --version
gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0