[build] Add detection of QNX platform (#34418)

include/grpc/support/port_platform.h

@@ -502,6 +502,24 @@
 #else /* _LP64 */
 #define GPR_ARCH_32 1
 #endif /* _LP64 */
+#elif defined(__QNX__) || defined(__QNXNTO__)
+#define GPR_PLATFORM_STRING "qnx"
+#define GPR_CPU_POSIX 1
+#define GPR_GCC_ATOMIC 1
+#define GPR_POSIX_LOG 1
+#define GPR_POSIX_ENV 1
+#define GPR_POSIX_TMPFILE 1
+#define GPR_POSIX_STAT 1
+#define GPR_POSIX_STRING 1
+#define GPR_POSIX_SYNC 1
+#define GPR_POSIX_TIME 1
+#define GPR_HAS_PTHREAD_H 1
+#define GPR_GETPID_IN_UNISTD_H 1
+#ifdef _LP64
+#define GPR_ARCH_64 1
+#else /* _LP64 */
+#define GPR_ARCH_32 1
+#endif /* _LP64 */
 #else
 #error "Could not auto-detect platform"
 #endif

src/core/lib/iomgr/port.h

@@ -209,6 +209,20 @@
 #define GRPC_POSIX_SOCKET 1
 #define GRPC_POSIX_SOCKETUTILS 1
 #define GRPC_POSIX_WAKEUP_FD 1
+#elif defined(__QNX__) || defined(__QNXNTO__)
+#define GRPC_HAVE_ARPA_NAMESER 1
+#define GRPC_HAVE_IFADDRS 1
+#define GRPC_HAVE_IPV6_RECVPKTINFO 1
+#define GRPC_HAVE_IP_PKTINFO 1
+#define GRPC_HAVE_MSG_NOSIGNAL 1
+#define GRPC_HAVE_UNIX_SOCKET 1
+// TODO(rbyshliaha): Find a way to understand if VSOCK package is installed in
+//                   a toolchain to enable GRPC_HAVE_VSOCK.
+#define GRPC_POSIX_SOCKET 1
+#define GRPC_POSIX_WAKEUP_FD 1
+#define GRPC_POSIX_NO_SPECIAL_WAKEUP_FD 1
+#define GRPC_POSIX_SOCKETUTILS 1
+#define GRPC_POSIX_SYSCONF 1
 #elif !defined(GPR_NO_AUTODETECT_PLATFORM)
 #error "Platform not recognized"
 #endif