setjmp.h: increase riscv64 jmp_buf size.
If we switch from x18 to gp for shadow call stack, we're going to need
another slot in jmp_buf. We'll need this even for hardware shadow call
stacks too.
While I'm here, and because this is likely my last chance, let's just
round this up to 32 for safety. musl and glibc only have the minimum
needed (which I think means they'll need an ABI break to support SCS
unless they just use a callee-saved general purpose register), but since
we can't do ABI breaks after we ship, let's play it safe.
Bug: https://github.com/google/android-riscv64/issues/72
Test: treehugger
Change-Id: I60661fb7a308c900bfd08c9361f51919b798c005
diff --git a/libc/include/setjmp.h b/libc/include/setjmp.h
index a3de9c7..141e925 100644
--- a/libc/include/setjmp.h
+++ b/libc/include/setjmp.h
@@ -53,7 +53,7 @@
#elif defined(__i386__)
#define _JBLEN 10
#elif defined(__riscv)
-#define _JBLEN 29
+#define _JBLEN 32
#elif defined(__x86_64__)
#define _JBLEN 11
#endif