mjhjmtu

I see this line in my binary:

0x0000000000000001 (NEEDED) Shared library: [libc.so.6]

Shouldn't I rather get rid of it? Actually more confusingly, why is it there in the first place, I feel like gcc by default compiling things that only run on the host machine is a bit crazy.
Isnt it super dangerous to just depend on some random libc that may or may not be on the machine that I'll eventually copy paste this binary to? I dont get it.
On Windows I think I'd get some kind of "missing runtime" error that is versioned to the exact runtime that I compiled it with, so if I compiled on XP with a certain compiler then any host machine has to have that runtime installed too.
But on Linux I've never heard of such a case, or is there a directory of 50 different libc.so somewhere and the right one gets linked when my application is trying to start up? Because I sort of have a feeling that .dll hell exists for real on Linux and this isn't actually the case.

At least with the GNU C library, linking carries version information for every single symbol (function etc.) that’s used. You can see this with objdump -T; for example, on /bin/ls, I get

DYNAMIC SYMBOL TABLE:
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.3 __ctype_toupper_loc
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 __uflow
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 getenv
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 sigprocmask
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.3.4 __snprintf_chk
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 raise
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 free
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 abort

etc.

The C library developers go to great lengths to ensure that the C library remains backwards compatible. The above output means that ls needs __ctype_toupper_loc from version 2.3 or later of the C library, etc. Any C library which provides all the required symbols will be able to run a given binary; and any given version of the GNU C library provides implementations of all the symbols which have ever been provided by an older version of the C library (going back to 1997).

Another way of handling things, used by most libraries on Linux-based systems (in fact, ELF-based systems and others), is the soname. Each library defines not only its name, but a version number, which is changed whenever breaking changes are introduced (in some cases, more often). Multiple versions of libraries, with different sonames, can be installed in parallel; for example

-rw-r--r-- 1 root root 2500416 Dec 16 21:07 libcrypto.so.1.0.2
-rw-r--r-- 1 root root 2711616 Nov 28 23:43 libcrypto.so.1.1

(This is also used by the C library, as evidenced by the dependency name, libc.so.6 — but the last GNU C library soname bump occurred many years ago.)

To address the question in your title, it is possible to statically link the C library, but it’s rarely necessary or useful (and can be confusing since some parts of the C library are dynamically linked even when the C library is statically linked). It can be useful to link other libraries statically. Other languages use different approaches, and for example Go programs are statically linked.