[gcc r14-6084] [committed] Fix frv build after C99 changes

[Jeff Law]

https://gcc.gnu.org/g:870b63fe71607b94c0e5b0c6e61cd807e0216ddd

commit r14-6084-g870b63fe71607b94c0e5b0c6e61cd807e0216ddd
Author: Jeff Law <jlaw@ventanamicro.com>
Date:   Sat Dec 2 21:54:36 2023 -0700

    [committed] Fix frv build after C99 changes
    
    Two issues prevent the frv-elf port from building after the C99 changes.  First
    the trampoline code emitted into libgcc has calls to exit, but no prototype.
    Adding a trivial prototype for exit() into the macro fixes that little goof.
    
    Second, frvbegin.c has a call to atexit, so a quick prototype is added into
    frvbegin.c to fix that problem.
    
    That's enough to get the compiler building again.
    
    gcc/
            * config/frv/frv.h (TRANSFER_FROM_TRAMPOLINE): Add prototype for exit.
    
    libgcc/
            * config/frv/frvbegin.c (atexit): Add prototype.

Diff:
---
 gcc/config/frv/frv.h         | 2 ++
 libgcc/config/frv/frvbegin.c | 1 +
 2 files changed, 3 insertions(+)

diff --git a/gcc/config/frv/frv.h b/gcc/config/frv/frv.h
index 979561126f8..93a7c6d0fcc 100644
--- a/gcc/config/frv/frv.h
+++ b/gcc/config/frv/frv.h
@@ -1241,6 +1241,7 @@ typedef struct frv_stack {
 #if ! __FRV_FDPIC__
 #define TRANSFER_FROM_TRAMPOLINE					\
 extern int Twrite (int, const void *, unsigned);			\
+extern void exit (int);							\
 									\
 void									\
 __trampoline_setup (short * addr, int size, int fnaddr, int sc)		\
@@ -1284,6 +1285,7 @@ __asm__("\n"								\
 #else
 #define TRANSFER_FROM_TRAMPOLINE					\
 extern int Twrite (int, const void *, unsigned);			\
+extern void exit (int);							\
 									\
 void									\
 __trampoline_setup (addr, size, fnaddr, sc)				\
diff --git a/libgcc/config/frv/frvbegin.c b/libgcc/config/frv/frvbegin.c
index 76b40ec46c6..24ea06b1ae7 100644
--- a/libgcc/config/frv/frvbegin.c
+++ b/libgcc/config/frv/frvbegin.c
@@ -119,6 +119,7 @@ __do_global_dtors (void)
     }
 }
 
+int atexit (void (*)(void));
 /* Run the global constructors.  */
 void
 __do_global_ctors (void)