[gcc r14-165] Fix up bootstrap with GCC 4.[89] after RAII auto_mpfr and autp_mpz [PR109589]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:195270d28a534cc1f08478c6e0136f4fc13d247a

commit r14-165-g195270d28a534cc1f08478c6e0136f4fc13d247a
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Apr 22 20:14:06 2023 +0200

    Fix up bootstrap with GCC 4.[89] after RAII auto_mpfr and autp_mpz [PR109589]
    
    On Tue, Apr 18, 2023 at 03:39:41PM +0200, Richard Biener via Gcc-patches wrote:
    > The following adds two RAII classes, one for mpz_t and one for mpfr_t
    > making object lifetime management easier.  Both formerly require
    > explicit initialization with {mpz,mpfr}_init and release with
    > {mpz,mpfr}_clear.
    
    This unfortunately broke bootstrap when using GCC 4.8.x or 4.9.x as
    it uses deleted friends which weren't supported until PR62101 fixed
    them in 2014 for GCC 5.
    
    The following patch adds an workaround, not deleting those friends
    for those old versions.
    While it means if people add those mp*_{init{,2},clear} calls on auto_mp*
    objects they won't notice when doing non-bootstrap builds using
    very old system compilers, people should be bootstrapping their changes
    and it will be caught during bootstraps even when starting with those
    old compilers, plus most people actually use much newer compilers
    when developing.
    
    2023-04-22  Jakub Jelinek  <jakub@redhat.com>
    
            PR bootstrap/109589
            * system.h (class auto_mpz): Workaround PR62101 bug in GCC 4.8 and 4.9.
            * realmpfr.h (class auto_mpfr): Likewise.

Diff:
---
 gcc/realmpfr.h | 3 +++
 gcc/system.h   | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/gcc/realmpfr.h b/gcc/realmpfr.h
index a2b1bf6a2db..c14baa2c1b5 100644
--- a/gcc/realmpfr.h
+++ b/gcc/realmpfr.h
@@ -37,9 +37,12 @@ public:
   auto_mpfr (const auto_mpfr &) = delete;
   auto_mpfr &operator= (const auto_mpfr &) = delete;
 
+#if GCC_VERSION < 4008 || GCC_VERSION >= 5000
+  /* GCC 4.8 and 4.9 don't support this, only fixed in PR62101 for 5.0.  */
   friend void mpfr_clear (auto_mpfr&) = delete;
   friend void mpfr_init (auto_mpfr&) = delete;
   friend void mpfr_init2 (auto_mpfr&, mpfr_prec_t) = delete;
+#endif
 
 private:
   mpfr_t m_mpfr;
diff --git a/gcc/system.h b/gcc/system.h
index c67bc42863f..5109c60c600 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -714,8 +714,11 @@ public:
   auto_mpz (const auto_mpz &) = delete;
   auto_mpz &operator= (const auto_mpz &) = delete;
 
+#if GCC_VERSION < 4008 || GCC_VERSION >= 5000
+  /* GCC 4.8 and 4.9 don't support this, only fixed in PR62101 for 5.0.  */
   friend void mpz_clear (auto_mpz&) = delete;
   friend void mpz_init (auto_mpz&) = delete;
+#endif
 
 private:
   mpz_t m_mpz;