glibc: version-gate _DYNAMIC_STACK_SIZE_SOURCE

This is a patch to glibc features.h which makes
_DYNAMIC_STACK_SIZE_SOURCE undefined unless the version is >= 2.34.

This feature was introduced with glibc 2.34 and without this patch, code
built against these headers but then run on an older glibc will end up
making a call to sysconf() that returns -1 for the value of SIGSTKSZ
and MINSIGSTKSZ.

Closes ziglang#10713

lib/libc/include/generic-glibc/features.h

@@ -220,8 +220,12 @@
 # define _DEFAULT_SOURCE	1
 # undef  _ATFILE_SOURCE
 # define _ATFILE_SOURCE	1
+
+# if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 34) || __GLIBC__ > 2
 # undef  _DYNAMIC_STACK_SIZE_SOURCE
 # define _DYNAMIC_STACK_SIZE_SOURCE 1
+# endif
+
 #endif
 
 /* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined,
@@ -512,4 +516,4 @@
 #include <gnu/stubs.h>
 
 
-#endif	/* features.h  */
+#endif	/* features.h  */