lib: remove backported cutPrefix implementation (ghostty-org#13658)

We can use std.mem.cutPrefix directly now that we're on Zig 0.16.

Author: mitchellh

src/apprt/gtk/class/application.zig

@@ -26,7 +26,6 @@ const xev = global.xev;
 const Binding = @import("../../../input.zig").Binding;
 const CoreConfig = configpkg.Config;
 const CoreSurface = @import("../../../Surface.zig");
-const lib = @import("../../../lib/main.zig");
 
 const ext = @import("../ext.zig");
 const key = @import("../key.zig");
@@ -1878,7 +1877,7 @@ pub const Application = extern struct {
                     continue;
                 }
 
-                if (lib.cutPrefix(u8, str, "--command=")) |v| {
+                if (std.mem.cutPrefix(u8, str, "--command=")) |v| {
                     var cmd: configpkg.Command = undefined;
                     cmd.parseCLI(alloc, v) catch |err| {
                         log.warn("unable to parse command: {t}", .{err});
@@ -1887,14 +1886,14 @@ pub const Application = extern struct {
                     command = cmd;
                     continue;
                 }
-                if (lib.cutPrefix(u8, str, "--working-directory=")) |v| {
+                if (std.mem.cutPrefix(u8, str, "--working-directory=")) |v| {
                     working_directory = alloc.dupeZ(u8, std.mem.trim(u8, v, &std.ascii.whitespace)) catch |err| wd: {
                         log.warn("unable to duplicate working directory: {t}", .{err});
                         break :wd null;
                     };
                     continue;
                 }
-                if (lib.cutPrefix(u8, str, "--title=")) |v| {
+                if (std.mem.cutPrefix(u8, str, "--title=")) |v| {
                     title = alloc.dupeZ(u8, std.mem.trim(u8, v, &std.ascii.whitespace)) catch |err| t: {
                         log.warn("unable to duplicate title: {t}", .{err});
                         break :t null;

src/cli/new_window.zig

@@ -5,7 +5,6 @@ const Action = @import("../cli.zig").ghostty.Action;
 const apprt = @import("../apprt.zig");
 const args = @import("args.zig");
 const diagnostics = @import("diagnostics.zig");
-const lib = @import("../lib/main.zig");
 const homedir = @import("../os/homedir.zig");
 const global = @import("../global.zig");
 
@@ -70,12 +69,12 @@ pub const Options = struct {
         Allocator.Error;
 
     fn checkArg(self: *Options, alloc: Allocator, arg: []const u8) CheckArgError!?[:0]const u8 {
-        if (lib.cutPrefix(u8, arg, "--class=")) |rest| {
+        if (std.mem.cutPrefix(u8, arg, "--class=")) |rest| {
             self.class = try alloc.dupeZ(u8, std.mem.trim(u8, rest, &std.ascii.whitespace));
             return null;
         }
 
-        if (lib.cutPrefix(u8, arg, "--working-directory=")) |rest| {
+        if (std.mem.cutPrefix(u8, arg, "--working-directory=")) |rest| {
             const stripped = std.mem.trim(u8, rest, &std.ascii.whitespace);
             if (std.mem.eql(u8, stripped, "home")) return try alloc.dupeZ(u8, arg);
             if (std.mem.eql(u8, stripped, "inherit")) return try alloc.dupeZ(u8, arg);

src/lib/main.zig

@@ -13,7 +13,6 @@ pub const Struct = structpkg.Struct;
 pub const structSizedFieldFits = structpkg.sizedFieldFits;
 pub const Target = @import("target.zig").Target;
 pub const TaggedUnion = unionpkg.TaggedUnion;
-pub const cutPrefix = @import("string.zig").cutPrefix;
 
 test {
     std.testing.refAllDecls(@This());