diff --git a/lib/c/string.zig b/lib/c/string.zig
index 94b94c65e9a022a4fd626be8ee48882ee7794e7b..31a11b1ce95fd62ffa367c11e24d11c7025622c3 100644
--- a/lib/c/string.zig
+++ b/lib/c/string.zig
@@ -68,8 +68,12 @@ comptime {
 }
 
 fn memchr(ptr: *const anyopaque, value: c_int, len: usize) callconv(.c) ?*anyopaque {
+    const b: u8 = @truncate(@as(c_uint, @bitCast(value)));
     const bytes: [*]const u8 = @ptrCast(ptr);
-    return @constCast(bytes[std.mem.findScalar(u8, bytes[0..len], @truncate(@as(c_uint, @bitCast(value)))) orelse return null ..]);
+    for (0..len) |i| {
+        if (bytes[i] == b) return @constCast(&bytes[i]);
+    }
+    return null;
 }
 
 fn strcpy(noalias dst: [*]c_char, noalias src: [*:0]const c_char) callconv(.c) [*]c_char {
diff --git a/lib/c/wchar.zig b/lib/c/wchar.zig
index eb9611514141e53665b333308c85aa26054257a7..e8837247a0d6799e63796a46c918b55c647aa9f7 100644
--- a/lib/c/wchar.zig
+++ b/lib/c/wchar.zig
@@ -46,8 +46,11 @@ comptime {
     }
 }
 
-fn wmemchr(ptr: [*]const wchar_t, value: wchar_t, len: usize) callconv(.c) ?[*]wchar_t {
-    return @constCast(ptr[std.mem.findScalar(wchar_t, ptr[0..len], value) orelse return null ..]);
+fn wmemchr(ptr: [*]const wchar_t, value: wchar_t, len: usize) callconv(.c) ?*wchar_t {
+    for (0..len) |i| {
+        if (ptr[i] == value) return @constCast(&ptr[i]);
+    }
+    return null;
 }
 
 fn wmemcmp(a: [*]const wchar_t, b: [*]const wchar_t, len: usize) callconv(.c) c_int {