[gcc r14-6196] libiberty: Fix build with GCC < 7

[gcc r14-6196] libiberty: Fix build with GCC < 7

[Jakub Jelinek]

https://gcc.gnu.org/g:c73cc6fe6207b2863afa31a3be8ad87b70d3df0a

commit r14-6196-gc73cc6fe6207b2863afa31a3be8ad87b70d3df0a
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Dec 5 23:32:19 2023 +0100

    libiberty: Fix build with GCC < 7
    
    Tobias reported on IRC that the linker fails to build with GCC 4.8.5.
    In configure I've tried to use everything actually used in the sha1.c
    x86 hw implementation, but unfortunately I forgot about implicit function
    declarations.  GCC before 7 did have <cpuid.h> header and bit_SHA define
    and __get_cpuid function defined inline, but it didn't define
    __get_cpuid_count, which compiled fine (and the configure test is
    intentionally compile time only) due to implicit function declaration,
    but then failed to link when linking the linker, because
    __get_cpuid_count wasn't defined anywhere.
    
    The following patch fixes that by using what autoconf uses in AC_CHECK_DECL
    to make sure the functions are declared.
    
    2023-12-05  Jakub Jelinek  <jakub@redhat.com>
    
            * configure.ac (HAVE_X86_SHA1_HW_SUPPORT): Verify __get_cpuid and
            __get_cpuid_count are not implicitly declared.
            * configure: Regenerated.

Diff:
---
 libiberty/configure    | 2 ++
 libiberty/configure.ac | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/libiberty/configure b/libiberty/configure
index 10f38511463..5c69fee56c1 100755
--- a/libiberty/configure
+++ b/libiberty/configure
@@ -7667,6 +7667,8 @@ void foo (__m128i *buf, unsigned int e, __m128i msg0, __m128i msg1)
 int bar (void)
 {
   unsigned int eax, ebx, ecx, edx;
+  (void) __get_cpuid;
+  (void) __get_cpuid_count;
   if (__get_cpuid_count (7, 0, &eax, &ebx, &ecx, &edx)
       && (ebx & bit_SHA) != 0
       && __get_cpuid (1, &eax, &ebx, &ecx, &edx)
diff --git a/libiberty/configure.ac b/libiberty/configure.ac
index 96a61934ffd..0888e638896 100644
--- a/libiberty/configure.ac
+++ b/libiberty/configure.ac
@@ -771,6 +771,8 @@ void foo (__m128i *buf, unsigned int e, __m128i msg0, __m128i msg1)
 int bar (void)
 {
   unsigned int eax, ebx, ecx, edx;
+  (void) __get_cpuid;
+  (void) __get_cpuid_count;
   if (__get_cpuid_count (7, 0, &eax, &ebx, &ecx, &edx)
       && (ebx & bit_SHA) != 0
       && __get_cpuid (1, &eax, &ebx, &ecx, &edx)