arch/posix: Workaround race condition in glibc

[tpambor]

Explicitly link with libgcc_s to work around a race condition in glibc when dynamically loading libgcc_s in multiple threads.

The race condition was observed in the past in #87987 (comment) when running native_sim with CONFIG_REBOOT=y and CONFIG_NATIVE_SIM_REBOOT=y and rebooting quickly
from main(). As well as in the new boards.native_sim.reset_hw_info test that was temporarily disabled in #96765.

Most likely, this is caused by pthread_exit() and vprintf loading libgcc_s in two threads at the same time. The program then crashes with

libgcc_s.so.1 must be installed for pthread_exit to work
Aborted (core dumped)

With this PR, no crashes were observed for the following example (without sleeping) based on #87987 (comment):

diff --git a/samples/hello_world/prj.conf b/samples/hello_world/prj.conf
index b2a4ba59104..36d8008a72b 100644
--- a/samples/hello_world/prj.conf
+++ b/samples/hello_world/prj.conf
@@ -1 +1,3 @@
 # nothing here
+CONFIG_REBOOT=y
+CONFIG_NATIVE_SIM_REBOOT=y
\ No newline at end of file
diff --git a/samples/hello_world/src/main.c b/samples/hello_world/src/main.c
index c550ab461cb..4c3b037d42e 100644
--- a/samples/hello_world/src/main.c
+++ b/samples/hello_world/src/main.c
@@ -5,10 +5,14 @@
  */
 
 #include <stdio.h>
+#include <zephyr/kernel.h>
+#include <zephyr/sys/reboot.h>
 
 int main(void)
 {
        printf("Hello World! %s\n", CONFIG_BOARD_TARGET);
 
+       sys_reboot(SYS_REBOOT_WARM);
+
        return 0;
 }

[tpambor]

/cc @koalatux

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[tpambor]

Closing this in favor of #96812