abseil QNX build, based on lts_2021_11_02 (commit: 215105818)

lts_2021_11_02.patch

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 750a475..110a1b5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,6 +21,16 @@
 # and then issuing `yum install cmake3` on the command line.
 cmake_minimum_required(VERSION 3.5)
 
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+if (CMAKE_SYSTEM_NAME STREQUAL "QNX")
+    add_definitions(-D_QNX_SOURCE)
+    add_definitions(-D_XOPEN_SOURCE=500)
+    add_definitions(-DSIGSTKSZ=65536)
+    add_definitions(-DSA_ONSTACK=0x08000000)
+endif()
+
 # Compiler id for Apple Clang is now AppleClang.
 if (POLICY CMP0025)
   cmake_policy(SET CMP0025 NEW)
diff --git a/absl/base/config.h b/absl/base/config.h
index 585485c..47ad302 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -294,6 +294,10 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #else  // !defined(__APPLE__)
 #define ABSL_HAVE_THREAD_LOCAL 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_HAVE_THREAD_LOCAL
+#define ABSL_HAVE_THREAD_LOCAL 0
+#endif
 
 // There are platforms for which TLS should not be used even though the compiler
 // makes it seem like it's supported (Android NDK < r12b for example).
@@ -417,6 +421,10 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
     defined(__HAIKU__)
 #define ABSL_HAVE_MMAP 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_HAVE_MMAP
+#define ABSL_HAVE_MMAP 0
+#endif
 
 // ABSL_HAVE_PTHREAD_GETSCHEDPARAM
 //
@@ -428,6 +436,10 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
     defined(_AIX) || defined(__ros__)
 #define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_HAVE_PTHREAD_GETSCHEDPARAM
+#define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 0
+#endif
 
 // ABSL_HAVE_SCHED_GETCPU
 //
@@ -437,6 +449,10 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #elif defined(__linux__)
 #define ABSL_HAVE_SCHED_GETCPU 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_HAVE_SCHED_GETCPU
+#define ABSL_HAVE_SCHED_GETCPU 0
+#endif
 
 // ABSL_HAVE_SCHED_YIELD
 //
@@ -447,6 +463,10 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #elif defined(__linux__) || defined(__ros__) || defined(__native_client__)
 #define ABSL_HAVE_SCHED_YIELD 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_HAVE_SCHED_YIELD
+#define ABSL_HAVE_SCHED_YIELD 0
+#endif
 
 // ABSL_HAVE_SEMAPHORE_H
 //
@@ -462,6 +482,10 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #elif defined(__linux__) || defined(__ros__)
 #define ABSL_HAVE_SEMAPHORE_H 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_HAVE_SEMAPHORE_H
+#define ABSL_HAVE_SEMAPHORE_H 0
+#endif
 
 // ABSL_HAVE_ALARM
 //
@@ -491,6 +515,10 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 // other standard libraries
 #define ABSL_HAVE_ALARM 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_HAVE_ALARM
+#define ABSL_HAVE_ALARM 0
+#endif
 
 // ABSL_IS_LITTLE_ENDIAN
 // ABSL_IS_BIG_ENDIAN
diff --git a/absl/base/internal/low_level_alloc.h b/absl/base/internal/low_level_alloc.h
index db91951..8dd837f 100644
--- a/absl/base/internal/low_level_alloc.h
+++ b/absl/base/internal/low_level_alloc.h
@@ -39,6 +39,10 @@
 #elif !defined(ABSL_HAVE_MMAP) && !defined(_WIN32)
 #define ABSL_LOW_LEVEL_ALLOC_MISSING 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_LOW_LEVEL_ALLOC_MISSING
+#define ABSL_LOW_LEVEL_ALLOC_MISSING 1
+#endif
 
 // Using LowLevelAlloc with kAsyncSignalSafe isn't supported on Windows or
 // asm.js / WebAssembly.
@@ -49,6 +53,10 @@
 #elif defined(_WIN32) || defined(__asmjs__) || defined(__wasm__)
 #define ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING 1
 #endif
+#if defined(__QNX__)
+#undef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
+#define ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING 1
+#endif
 
 #include <cstddef>
 
diff --git a/absl/debugging/failure_signal_handler.cc b/absl/debugging/failure_signal_handler.cc
index 689e597..9a16c41 100644
--- a/absl/debugging/failure_signal_handler.cc
+++ b/absl/debugging/failure_signal_handler.cc
@@ -167,9 +167,13 @@ static bool SetupAlternateStackOnce() {
   }
 #endif
 
+#if defined(__QNX__)
+    // ABSL_RAW_LOG(FATAL, "sigaltstack() not supported");
+#else
   if (sigaltstack(&sigstk, nullptr) != 0) {
     ABSL_RAW_LOG(FATAL, "sigaltstack() failed with errno=%d", errno);
   }
+#endif
   return true;
 }
 
@@ -347,7 +351,7 @@ static void AbslFailureSignalHandler(int signo, siginfo_t*, void* ucontext) {
   // signal was received by doing this as early as possible, i.e. after
   // verifying that this is not a recursive signal handler invocation.
   int my_cpu = -1;
-#ifdef ABSL_HAVE_SCHED_GETCPU
+#if ABSL_HAVE_SCHED_GETCPU
   my_cpu = sched_getcpu();
 #endif
 
diff --git a/absl/debugging/internal/elf_mem_image.h b/absl/debugging/internal/elf_mem_image.h
index a894bd4..fb0de63 100644
--- a/absl/debugging/internal/elf_mem_image.h
+++ b/absl/debugging/internal/elf_mem_image.h
@@ -35,6 +35,11 @@
     !defined(__wasm__)
 #define ABSL_HAVE_ELF_MEM_IMAGE 1
 #endif
+#if defined(__QNX__)
+#ifdef ABSL_HAVE_ELF_MEM_IMAGE
+#undef ABSL_HAVE_ELF_MEM_IMAGE
+#endif
+#endif
 
 #ifdef ABSL_HAVE_ELF_MEM_IMAGE
 
diff --git a/absl/random/internal/nanobenchmark.cc b/absl/random/internal/nanobenchmark.cc
index c918181..13a3f0e 100644
--- a/absl/random/internal/nanobenchmark.cc
+++ b/absl/random/internal/nanobenchmark.cc
@@ -708,7 +708,7 @@ void PinThreadToCPU(int cpu) {
   }
   const DWORD_PTR prev = SetThreadAffinityMask(GetCurrentThread(), 1ULL << cpu);
   ABSL_RAW_CHECK(prev != 0, "SetAffinity failed");
-#elif defined(ABSL_OS_LINUX) && !defined(ABSL_OS_ANDROID)
+#elif defined(ABSL_OS_LINUX) && !defined(ABSL_OS_ANDROID) && ABSL_HAVE_SCHED_GETCPU
   if (cpu < 0) {
     cpu = sched_getcpu();
     ABSL_RAW_CHECK(cpu >= 0, "PinThreadToCPU detect failed");
diff --git a/conanfile.py b/conanfile.py
index 926ec5c..53c7bb3 100755
--- a/conanfile.py
+++ b/conanfile.py
@@ -5,6 +5,7 @@
 # internally, so we won't know if it stops working. We may ask community
 # members to help us debug any problems that arise.
 
+import os
 from conans import ConanFile, CMake, tools
 from conans.errors import ConanInvalidConfiguration
 from conans.model.version import Version
@@ -44,8 +45,8 @@ class AbseilConan(ConanFile):
         self.copy("*.lib", dst="lib", src=".", keep_path=False)
 
     def package_info(self):
-        if self.settings.os == "Linux":
-            self.cpp_info.libs = ["-Wl,--start-group"]
+        self.cpp_info.libs = ['-Wl,--start-group']
         self.cpp_info.libs.extend(tools.collect_libs(self))
-        if self.settings.os == "Linux":
-            self.cpp_info.libs.extend(["-Wl,--end-group", "pthread"])
+        self.cpp_info.libs.append('-Wl,--end-group')
+        if self.settings.os == 'Linux':
+            self.cpp_info.libs.append('pthread')

for older version

see https://gist.github.com/district10/9937754bdcdd5321a56430f491088de9