openjdk{8,11}: fix build with gcc15

- add "-std=gnu17" to `env.NIX_CFLAGS_COMPILE` for `openjdk8` and `openjdk11`

Similar to what archlinux and gentoo did:
https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=65ea75ab7b558c1a7471eaf9ab542cee66631ea5
https://gitlab.archlinux.org/archlinux/packaging/packages/java8-openjdk/-/commit/e2b65f230bb5f15b75377306f41635ba44f84f61
https://gitlab.archlinux.org/archlinux/packaging/packages/java11-openjdk/-/commit/87ced23f8bd6b7e911f8b668545aa8c9950087e9

Fixes build failure of `openjdk8` with gcc15:
```
In file included from /build/source/hotspot/agent/src/os/linux/libproc_impl.h:30,
                 from /build/source/hotspot/agent/src/os/linux/salibelf.h:30,
                 from /build/source/hotspot/agent/src/os/linux/salibelf.c:25:
/build/source/hotspot/agent/src/os/linux/libproc.h:86:13: error: 'bool'
cannot be defined via 'typedef'
   86 | typedef int bool;
      |             ^~~~
/build/source/hotspot/agent/src/os/linux/libproc.h:86:13: note: 'bool'
is a keyword with '-std=c23' onwards
```

Fixes build failure of `openjdk11` with gcc15:
```
/build/source/src/java.base/unix/native/libnet/DefaultProxySelector.c:
In function 'getProxyByGProxyResolver':
/build/source/src/java.base/unix/native/libnet/DefaultProxySelector.c:389:16:
error: too many arguments to function 'g_proxy_resolver_lookup'; expected 0, have 4
  389 |     proxies = (*g_proxy_resolver_lookup)(resolver, uri, NULL, &error);
      |               ~^~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~
/build/source/src/java.base/unix/native/libnet/DefaultProxySelector.c:408:34:
error: too many arguments to function 'g_network_address_parse_uri'; expected 0, have 3
  408 |                                 (*g_network_address_parse_uri)(proxies[i], 0,
      |                                 ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~
```

0 files changed, 0 insertions, 0 deletions