diff -ruN llvm-project-20.1.8.src/llvm/include/llvm/ADT/bit.h llvm-project-20.1.8.src-banan_os/llvm/include/llvm/ADT/bit.h
--- llvm-project-20.1.8.src/llvm/include/llvm/ADT/bit.h	2025-07-09 02:06:32.000000000 +0300
+++ llvm-project-20.1.8.src-banan_os/llvm/include/llvm/ADT/bit.h	2025-08-03 17:05:07.723852159 +0300
@@ -29,7 +29,7 @@
 
 #if defined(__linux__) || defined(__GNU__) || defined(__HAIKU__) ||            \
     defined(__Fuchsia__) || defined(__EMSCRIPTEN__) || defined(__NetBSD__) ||  \
-    defined(__OpenBSD__) || defined(__DragonFly__)
+    defined(__OpenBSD__) || defined(__DragonFly__) || defined(__banan_os__)
 #include <endian.h>
 #elif defined(_AIX)
 #include <sys/machine.h>
diff -ruN llvm-project-20.1.8.src/llvm/include/llvm/Support/ExitCodes.h llvm-project-20.1.8.src-banan_os/llvm/include/llvm/Support/ExitCodes.h
--- llvm-project-20.1.8.src/llvm/include/llvm/Support/ExitCodes.h	2025-07-09 02:06:32.000000000 +0300
+++ llvm-project-20.1.8.src-banan_os/llvm/include/llvm/Support/ExitCodes.h	2025-08-03 17:05:35.659696821 +0300
@@ -20,6 +20,8 @@
 
 #if HAVE_SYSEXITS_H
 #include <sysexits.h>
+#elif defined(__banan_os__)
+#define EX_IOERR 69
 #elif __MVS__ || defined(_WIN32)
 // <sysexits.h> does not exist on z/OS and Windows. The only value used in LLVM
 // is EX_IOERR, which is used to signal a special error condition (broken pipe).
diff -ruN llvm-project-20.1.8.src/llvm/lib/Support/Unix/Path.inc llvm-project-20.1.8.src-banan_os/llvm/lib/Support/Unix/Path.inc
--- llvm-project-20.1.8.src/llvm/lib/Support/Unix/Path.inc	2025-07-09 02:06:32.000000000 +0300
+++ llvm-project-20.1.8.src-banan_os/llvm/lib/Support/Unix/Path.inc	2025-08-03 17:06:42.941322766 +0300
@@ -107,7 +107,7 @@
 #endif
 
 #if defined(__NetBSD__) || defined(__DragonFly__) || defined(__GNU__) ||       \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__banan_os__)
 #define STATVFS_F_FLAG(vfs) (vfs).f_flag
 #else
 #define STATVFS_F_FLAG(vfs) (vfs).f_flags
@@ -317,6 +317,9 @@
       return std::string(real_path);
     break; // Found entry, but realpath failed.
   }
+#elif defined(__banan_os__)
+  fprintf(stddbg, "TODO: getMainExecutable\n");
+  return "";
 #elif defined(HAVE_DLOPEN)
   // Use dladdr to get executable path if available.
   Dl_info DLInfo;
@@ -506,6 +509,9 @@
 #elif defined(__HAIKU__)
   // Haiku doesn't expose this information.
   return false;
+#elif defined(__banan_os__)
+  // banan-os doesn't currently support remote filesystem mounts.
+  return true;
 #elif defined(__sun)
   // statvfs::f_basetype contains a null-terminated FSType name of the mounted
   // target
diff -ruN llvm-project-20.1.8.src/llvm/lib/Support/Unix/Program.inc llvm-project-20.1.8.src-banan_os/llvm/lib/Support/Unix/Program.inc
--- llvm-project-20.1.8.src/llvm/lib/Support/Unix/Program.inc	2025-07-09 02:06:32.000000000 +0300
+++ llvm-project-20.1.8.src-banan_os/llvm/lib/Support/Unix/Program.inc	2025-08-03 17:04:50.500947936 +0300
@@ -342,7 +342,7 @@
 namespace llvm {
 namespace sys {
 
-#if defined(_AIX)
+#if defined(_AIX) || defined(__banan_os__)
 static pid_t(wait4)(pid_t pid, int *status, int options, struct rusage *usage);
 #elif !defined(__Fuchsia__)
 using ::wait4;
@@ -383,6 +383,17 @@
   // would cause the call here to fail with ECHILD).
   return ::wait4(pid, status, options & ~WNOHANG, usage);
 }
+#elif defined(__banan_os__)
+
+#ifndef _ALL_SOURCE
+extern "C" pid_t(wait4)(pid_t pid, int *status, int options,
+                        struct rusage *usage);
+#endif
+pid_t(llvm::sys::wait4)(pid_t pid, int *status, int options,
+                        struct rusage *usage) {
+    memset(usage, 0, sizeof(struct rusage));
+       return waitpid(pid, status, options);
+}
 #endif
 
 ProcessInfo llvm::sys::Wait(const ProcessInfo &PI,
@@ -468,7 +479,7 @@
     std::chrono::microseconds UserT = toDuration(Info.ru_utime);
     std::chrono::microseconds KernelT = toDuration(Info.ru_stime);
     uint64_t PeakMemory = 0;
-#if !defined(__HAIKU__) && !defined(__MVS__)
+#if !defined(__HAIKU__) && !defined(__MVS__) && !defined(__banan_os__)
     PeakMemory = static_cast<uint64_t>(Info.ru_maxrss);
 #endif
     *ProcStat = ProcessStatistics{UserT + KernelT, UserT, PeakMemory};
diff -ruN llvm-project-20.1.8.src/llvm/lib/Support/Unix/Signals.inc llvm-project-20.1.8.src-banan_os/llvm/lib/Support/Unix/Signals.inc
--- llvm-project-20.1.8.src/llvm/lib/Support/Unix/Signals.inc	2025-07-09 02:06:32.000000000 +0300
+++ llvm-project-20.1.8.src-banan_os/llvm/lib/Support/Unix/Signals.inc	2025-08-03 17:03:20.739447219 +0300
@@ -817,7 +817,7 @@
   OS << "Stack dump without symbol names (ensure you have llvm-symbolizer in "
         "your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point "
         "to it):\n";
-#if HAVE_DLOPEN && !defined(_AIX)
+#if HAVE_DLOPEN && !defined(_AIX) && !defined(__banan_os__)
   int width = 0;
   for (int i = 0; i < depth; ++i) {
     Dl_info dlinfo;