[gcc r11-5211] libada: Check for the presence of _SC_NPROCESSORS_ONLN

[Maciej W. Rozycki <macro@gcc.gnu.org>]

https://gcc.gnu.org/g:9e071b6e5ed5a07a4ce621382904c084431f9d47

commit r11-5211-g9e071b6e5ed5a07a4ce621382904c084431f9d47
Author: Maciej W. Rozycki <macro@linux-mips.org>
Date:   Fri Nov 20 21:11:22 2020 +0000

    libada: Check for the presence of _SC_NPROCESSORS_ONLN
    
    Check for the presence of _SC_NPROCESSORS_ONLN rather than using a list
    of OS-specific macros to decide whether to use `sysconf' like elsewhere
    across GCC sources, fixing a compilation error:
    
    adaint.c: In function '__gnat_number_of_cpus':
    adaint.c:2398:26: error: '_SC_NPROCESSORS_ONLN' undeclared (first use in this function)
     2398 |   cores = (int) sysconf (_SC_NPROCESSORS_ONLN);
          |                          ^~~~~~~~~~~~~~~~~~~~
    adaint.c:2398:26: note: each undeclared identifier is reported only once for each function it appears in
    
    at least with with VAX/NetBSD 1.6.2.
    
            gcc/ada/
            * adaint.c (__gnat_number_of_cpus): Check for the presence of
            _SC_NPROCESSORS_ONLN rather than a list of OS-specific macros
            to decide whether to use `sysconf'.

Diff:
---
 gcc/ada/adaint.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/gcc/ada/adaint.c b/gcc/ada/adaint.c
index f5432626ee6..554123c905b 100644
--- a/gcc/ada/adaint.c
+++ b/gcc/ada/adaint.c
@@ -2483,9 +2483,7 @@ __gnat_number_of_cpus (void)
 {
   int cores = 1;
 
-#if defined (__linux__) || defined (__sun__) || defined (_AIX) \
-  || defined (__APPLE__) || defined (__FreeBSD__) || defined (__OpenBSD__) \
-  || defined (__DragonFly__) || defined (__NetBSD__)
+#ifdef _SC_NPROCESSORS_ONLN
   cores = (int) sysconf (_SC_NPROCESSORS_ONLN);
 
 #elif defined (__QNX__)