diff --git a/lib/std/c/haiku.zig b/lib/std/c/haiku.zig
index 4706181bb95e..f4c928c79c48 100644
--- a/lib/std/c/haiku.zig
+++ b/lib/std/c/haiku.zig
@@ -110,21 +110,6 @@ pub const socklen_t = u32;
 // Modes and flags for dlopen()
 // include/dlfcn.h
 
-pub const POLL = struct {
-    /// input available
-    pub const IN = 70;
-    /// output available
-    pub const OUT = 71;
-    /// input message available
-    pub const MSG = 72;
-    /// I/O error
-    pub const ERR = 73;
-    /// high priority input available
-    pub const PRI = 74;
-    /// device disconnected
-    pub const HUP = 75;
-};
-
 pub const RTLD = struct {
     /// relocations are performed as needed
     pub const LAZY = 0;
@@ -177,14 +162,6 @@ pub const msghdr = extern struct {
 pub const off_t = i64;
 pub const ino_t = u64;
 
-pub const nfds_t = u32;
-
-pub const pollfd = extern struct {
-    fd: i32,
-    events: i16,
-    revents: i16,
-};
-
 pub const Stat = extern struct {
     dev: i32,
     ino: u64,
@@ -427,7 +404,39 @@ pub const W = struct {
     }
 };
 
-// posix/signal.h
+// /system/develop/headers/posix/poll.h
+
+pub const nfds_t = usize;
+
+pub const pollfd = extern struct {
+    fd: i32,
+    events: i16,
+    revents: i16,
+};
+
+pub const POLL = struct {
+    /// any readable data available
+    pub const IN = 0x0001;
+    /// file descriptor is writeable
+    pub const OUT = 0x0002;
+    pub const RDNORM = IN;
+    pub const WRNORM = OUT;
+    /// priority readable data
+    pub const RDBAND = 0x0008;
+    /// priority data can be written
+    pub const WRBAND = 0x0010;
+    /// high priority readable data
+    pub const PRI = 0x0020;
+
+    /// errors pending
+    pub const ERR = 0x0004;
+    /// disconnected
+    pub const HUP = 0x0080;
+    /// invalid file descriptor
+    pub const NVAL = 0x1000;
+};
+
+// /system/develop/headers/posix/signal.h
 
 pub const sigset_t = u64;
 pub const empty_sigset: sigset_t = 0;
@@ -548,7 +557,7 @@ pub const ucontext_t = extern struct {
     mcontext: mcontext_t,
 };
 
-// arch/*/signal.h
+// /system/develop/headers/posix/arch/*/signal.h
 
 pub const vregs = switch (builtin.cpu.arch) {
     .arm, .thumb => extern struct {
diff --git a/lib/std/io.zig b/lib/std/io.zig
index d0432d1ff910..9f0f444a8365 100644
--- a/lib/std/io.zig
+++ b/lib/std/io.zig
@@ -610,10 +610,7 @@ pub fn Poller(comptime StreamEnum: type) type {
             // allocate grows exponentially.
             const bump_amt = 512;
 
-            const err_mask = switch (builtin.target.os.tag) {
-                .haiku => posix.POLL.ERR | posix.POLL.HUP,
-                else => posix.POLL.ERR | posix.POLL.NVAL | posix.POLL.HUP,
-            };
+            const err_mask = posix.POLL.ERR | posix.POLL.NVAL | posix.POLL.HUP;
 
             const events_len = try posix.poll(&self.poll_fds, if (nanoseconds) |ns|
                 std.math.cast(i32, ns / std.time.ns_per_ms) orelse std.math.maxInt(i32)
diff --git a/lib/std/zig/LibCInstallation.zig b/lib/std/zig/LibCInstallation.zig
index 3305d9484ded..2a4e7d4b5b09 100644
--- a/lib/std/zig/LibCInstallation.zig
+++ b/lib/std/zig/LibCInstallation.zig
@@ -67,34 +67,34 @@ pub fn parse(
     }
     inline for (fields, 0..) |field, i| {
         if (!found_keys[i].found) {
-            log.err("missing field: {s}\n", .{field.name});
+            log.err("missing field: {s}", .{field.name});
             return error.ParseError;
         }
     }
     if (self.include_dir == null) {
-        log.err("include_dir may not be empty\n", .{});
+        log.err("include_dir may not be empty", .{});
         return error.ParseError;
     }
     if (self.sys_include_dir == null) {
-        log.err("sys_include_dir may not be empty\n", .{});
+        log.err("sys_include_dir may not be empty", .{});
         return error.ParseError;
     }
 
     const os_tag = target.os.tag;
     if (self.crt_dir == null and !target.isDarwin()) {
-        log.err("crt_dir may not be empty for {s}\n", .{@tagName(os_tag)});
+        log.err("crt_dir may not be empty for {s}", .{@tagName(os_tag)});
         return error.ParseError;
     }
 
     if (self.msvc_lib_dir == null and os_tag == .windows and target.abi == .msvc) {
-        log.err("msvc_lib_dir may not be empty for {s}-{s}\n", .{
+        log.err("msvc_lib_dir may not be empty for {s}-{s}", .{
             @tagName(os_tag),
             @tagName(target.abi),
         });
         return error.ParseError;
     }
     if (self.kernel32_lib_dir == null and os_tag == .windows and target.abi == .msvc) {
-        log.err("kernel32_lib_dir may not be empty for {s}-{s}\n", .{
+        log.err("kernel32_lib_dir may not be empty for {s}-{s}", .{
             @tagName(os_tag),
             @tagName(target.abi),
         });
@@ -102,7 +102,7 @@ pub fn parse(
     }
 
     if (self.gcc_dir == null and os_tag == .haiku) {
-        log.err("gcc_dir may not be empty for {s}\n", .{@tagName(os_tag)});
+        log.err("gcc_dir may not be empty for {s}", .{@tagName(os_tag)});
         return error.ParseError;
     }
 
diff --git a/lib/std/zig/system.zig b/lib/std/zig/system.zig
index b7a5284be9f0..c9fe14a1c6f2 100644
--- a/lib/std/zig/system.zig
+++ b/lib/std/zig/system.zig
@@ -1017,7 +1017,7 @@ fn detectAbiAndDynamicLinker(
                 error.FileTooBig,
                 error.Unexpected,
                 => |e| {
-                    std.log.warn("Encountered error: {s}, falling back to default ABI and dynamic linker.\n", .{@errorName(e)});
+                    std.log.warn("Encountered error: {s}, falling back to default ABI and dynamic linker.", .{@errorName(e)});
                     return defaultAbiAndDynamicLinker(cpu, os, query);
                 },
 
@@ -1065,7 +1065,7 @@ fn detectAbiAndDynamicLinker(
         error.NameTooLong,
         // Finally, we fall back on the standard path.
         => |e| {
-            std.log.warn("Encountered error: {s}, falling back to default ABI and dynamic linker.\n", .{@errorName(e)});
+            std.log.warn("Encountered error: {s}, falling back to default ABI and dynamic linker.", .{@errorName(e)});
             return defaultAbiAndDynamicLinker(cpu, os, query);
         },
     };