[OpenMP] Provide __NR_sched_[gs]etaffinity on Linux/sparc64 (llvm#138525)

`libomp` doesn't currently build on Linux/sparc64 due to lack of
`__NR_sched_setaffinity` and `__NR_sched_getaffinity` definitions.

This patch provides those.

Tested on `sparcv9-sun-solaris2.11`, `sparc64-unknown-linux-gnu`,
`amd64-pc-solaris2.11`, and `x86_64-pc-linux-gnu`.

Author: rorth

openmp/runtime/src/kmp_affinity.h

@@ -311,6 +311,17 @@ class KMPHwlocAffinity : public KMPAffinity {
 #elif __NR_sched_getaffinity != 240
 #error Wrong code for getaffinity system call.
 #endif /* __NR_sched_getaffinity */
+#elif KMP_ARCH_SPARC
+#ifndef __NR_sched_setaffinity
+#define __NR_sched_setaffinity 261
+#elif __NR_sched_setaffinity != 261
+#error Wrong code for setaffinity system call.
+#endif /* __NR_sched_setaffinity */
+#ifndef __NR_sched_getaffinity
+#define __NR_sched_getaffinity 260
+#elif __NR_sched_getaffinity != 260
+#error Wrong code for getaffinity system call.
+#endif /* __NR_sched_getaffinity */
 #else
 #error Unknown or unsupported architecture
 #endif /* KMP_ARCH_* */