diff --git a/absl/base/config.h b/absl/base/config.h
index 58077a2c58f..abaa29353bf 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -380,7 +380,8 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
     defined(__asmjs__) || defined(__EMSCRIPTEN__) || defined(__Fuchsia__) || \
     defined(__sun) || defined(__myriad2__) || defined(__HAIKU__) ||          \
     defined(__OpenBSD__) || defined(__NetBSD__) || defined(__QNX__) ||       \
-    defined(__VXWORKS__) || defined(__hexagon__) || defined(__XTENSA__)
+    defined(__VXWORKS__) || defined(__hexagon__) || defined(__XTENSA__) ||   \
+    defined(__GNU__)
 #define ABSL_HAVE_MMAP 1
 #endif
 
diff --git a/absl/base/internal/raw_logging.cc b/absl/base/internal/raw_logging.cc
index 35a08f0ac03..e332a90283c 100644
--- a/absl/base/internal/raw_logging.cc
+++ b/absl/base/internal/raw_logging.cc
@@ -44,7 +44,7 @@
 #if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \
     defined(__hexagon__) || defined(__Fuchsia__) ||                     \
     defined(__native_client__) || defined(__OpenBSD__) ||               \
-    defined(__EMSCRIPTEN__) || defined(__ASYLO__)
+    defined(__EMSCRIPTEN__) || defined(__ASYLO__) || defined(__GNU__)
 
 #include <unistd.h>
 
diff --git a/absl/base/internal/strerror_test.cc b/absl/base/internal/strerror_test.cc
index e32d5b5c9be..2eccde7709c 100644
--- a/absl/base/internal/strerror_test.cc
+++ b/absl/base/internal/strerror_test.cc
@@ -39,7 +39,9 @@ TEST(StrErrorTest, ValidErrorCode) {
 TEST(StrErrorTest, InvalidErrorCode) {
   errno = ERANGE;
   EXPECT_THAT(absl::base_internal::StrError(-1),
-              AnyOf(Eq("No error information"), Eq("Unknown error -1")));
+              AnyOf(Eq("No error information"),
+                    Eq("Unknown error -1"),
+                    Eq("Error in unknown error system: FFFFFFFF")));
   EXPECT_THAT(errno, Eq(ERANGE));
 }
 
diff --git a/absl/debugging/internal/stack_consumption.h b/absl/debugging/internal/stack_consumption.h
index f5ba5575d1b..3dac5207b64 100644
--- a/absl/debugging/internal/stack_consumption.h
+++ b/absl/debugging/internal/stack_consumption.h
@@ -25,7 +25,8 @@
 #ifdef ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
 #error ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION cannot be set directly
 #elif !defined(__APPLE__) && !defined(_WIN32) && !defined(__Fuchsia__) && \
-    (defined(__i386__) || defined(__x86_64__) || defined(__ppc__) || \
+    !defined(__GNU__) &&                                                  \
+    (defined(__i386__) || defined(__x86_64__) || defined(__ppc__) ||      \
      defined(__aarch64__) || defined(__riscv))
 #define ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION 1
 
diff --git a/absl/debugging/internal/symbolize.h b/absl/debugging/internal/symbolize.h
index 5593fde6b4c..8e2d7c8eb05 100644
--- a/absl/debugging/internal/symbolize.h
+++ b/absl/debugging/internal/symbolize.h
@@ -29,7 +29,7 @@
 #ifdef ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE
 #error ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE cannot be directly set
 #elif defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) \
-      && !defined(__asmjs__) && !defined(__wasm__)
+      && !defined(__asmjs__) && !defined(__wasm__) && !defined(__GNU__)
 #define ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE 1
 
 #include <elf.h>
diff --git a/absl/debugging/internal/vdso_support.h b/absl/debugging/internal/vdso_support.h
index 6562c6c2350..cfca78d3540 100644
--- a/absl/debugging/internal/vdso_support.h
+++ b/absl/debugging/internal/vdso_support.h
@@ -48,7 +48,7 @@
 
 #ifdef ABSL_HAVE_VDSO_SUPPORT
 #error ABSL_HAVE_VDSO_SUPPORT cannot be directly set
-#else
+#elif !defined(__GNU__)
 #define ABSL_HAVE_VDSO_SUPPORT 1
 #endif
 
diff --git a/absl/log/internal/test_helpers.cc b/absl/log/internal/test_helpers.cc
index bfcc9679607..0f5640bbeef 100644
--- a/absl/log/internal/test_helpers.cc
+++ b/absl/log/internal/test_helpers.cc
@@ -18,6 +18,8 @@
 #include <zircon/syscalls.h>
 #endif
 
+#include <signal.h>
+
 #include "gtest/gtest.h"
 #include "absl/base/config.h"
 #include "absl/base/log_severity.h"
diff --git a/absl/log/log_modifier_methods_test.cc b/absl/log/log_modifier_methods_test.cc
index fc98e1f679e..f945e837cea 100644
--- a/absl/log/log_modifier_methods_test.cc
+++ b/absl/log/log_modifier_methods_test.cc
@@ -181,13 +181,16 @@ TEST(TailCallsModifiesTest, WithPerror) {
       Send(AllOf(
           TextMessage(AnyOf(Eq("hello world: Bad file number [9]"),
                             Eq("hello world: Bad file descriptor [9]"),
-                            Eq("hello world: Bad file descriptor [8]"))),
+                            Eq("hello world: Bad file descriptor [8]"),
+                            Eq("hello world: Bad file descriptor [1073741833]"))),
           ENCODED_MESSAGE(HasValues(ElementsAre(
               ValueWithLiteral(Eq("hello world")), ValueWithLiteral(Eq(": ")),
               AnyOf(ValueWithStr(Eq("Bad file number")),
                     ValueWithStr(Eq("Bad file descriptor"))),
               ValueWithLiteral(Eq(" [")),
-              AnyOf(ValueWithStr(Eq("8")), ValueWithStr(Eq("9"))),
+              AnyOf(ValueWithStr(Eq("8")),
+                    ValueWithStr(Eq("9")),
+                    ValueWithStr(Eq("1073741833"))),
               ValueWithLiteral(Eq("]"))))))));
 
   test_sink.StartCapturingLogs();
diff --git a/absl/log/stripping_test.cc b/absl/log/stripping_test.cc
index 271fae1d8dc..20231b9fa6c 100644
--- a/absl/log/stripping_test.cc
+++ b/absl/log/stripping_test.cc
@@ -33,7 +33,7 @@
 
 #include <stdio.h>
 
-#if defined(__MACH__)
+#if defined(__APPLE__)
 #include <mach-o/dyld.h>
 #elif defined(_WIN32)
 #include <Windows.h>
@@ -191,7 +191,7 @@ class StrippingTest : public ::testing::Test {
       absl::FPrintF(stderr, "Failed to open /pkg/bin/<binary name>: %s\n", err);
     }
     return fp;
-#elif defined(__MACH__)
+#elif defined(__APPLE__)
     uint32_t size = 0;
     int ret = _NSGetExecutablePath(nullptr, &size);
     if (ret != -1) {