posix: Add sysconf(_SC_{MIN,}SIGSTKSZ) support

sysdeps/posix/sysconf.c

@@ -31,6 +31,7 @@
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <regex.h>
+#include <signal.h>
 #include <sysconf-pthread_stack_min.h>
 
 #define NEED_SPEC_ARRAY 0
@@ -1190,6 +1191,20 @@ __sysconf (int name)
 #else
       return -1;
 #endif
+
+    case _SC_SIGSTKSZ:
+#ifdef SIGSTKSZ
+      return SIGSTKSZ;
+#else
+      return -1;
+#endif
+
+    case _SC_MINSIGSTKSZ:
+#ifdef MINSIGSTKSZ
+      return MINSIGSTKSZ;
+#else
+      return -1;
+#endif
     }
 }