terminal: add lib.zig to centralize lib target and re-exports

Previously every file in the terminal package independently imported
build_options and ../lib/main.zig, then computed the same
lib_target constant. This was repetitive and meant each file needed
both imports just to get the target.

Introduce src/terminal/lib.zig which computes the target once and
re-exports the commonly used lib types (Enum, TaggedUnion, Struct,
String, checkGhosttyHEnum, structSizedFieldFits). All terminal
package files now import lib.zig and use lib.target instead of the
local lib_target constant, removing the per-file boilerplate.

src/terminal/ScreenSet.zig

@@ -9,16 +9,13 @@ const ScreenSet = @This();
 
 const std = @import("std");
 const assert = @import("../quirks.zig").inlineAssert;
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
+const lib = @import("lib.zig");
 const testing = std.testing;
 const Allocator = std.mem.Allocator;
 const Screen = @import("Screen.zig");
 
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
-
 /// The possible keys for screens in the screen set.
-pub const Key = lib.Enum(lib_target, &.{
+pub const Key = lib.Enum(lib.target, &.{
     "primary",
     "alternate",
 });

src/terminal/Terminal.zig

@@ -5,7 +5,7 @@ const Terminal = @This();
 
 const std = @import("std");
 const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
+const lib = @import("lib.zig");
 const assert = @import("../quirks.zig").inlineAssert;
 const testing = std.testing;
 const Allocator = std.mem.Allocator;
@@ -35,8 +35,6 @@ const Page = pagepkg.Page;
 const Cell = pagepkg.Cell;
 const Row = pagepkg.Row;
 
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
-
 const log = std.log.scoped(.terminal);
 
 /// Default tabstop interval
@@ -1706,14 +1704,14 @@ pub const ScrollViewport = union(Tag) {
     /// Scroll by some delta amount, up is negative.
     delta: isize,
 
-    pub const Tag = lib.Enum(lib_target, &.{
+    pub const Tag = lib.Enum(lib.target, &.{
         "top",
         "bottom",
         "delta",
     });
 
     const c_union = lib.TaggedUnion(
-        lib_target,
+        lib.target,
         @This(),
         // Padding: largest variant is isize (8 bytes on 64-bit).
         // Use [2]u64 (16 bytes) for future expansion.

src/terminal/ansi.zig

@@ -1,6 +1,4 @@
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 
 /// C0 (7-bit) control characters from ANSI.
 ///
@@ -54,7 +52,7 @@ pub const RenditionAspect = enum(u16) {
 
 /// Possible cursor styles (ESC [ q)
 pub const CursorStyle = lib.Enum(
-    lib_target,
+    lib.target,
     &.{
         "default",
         "blinking_block",
@@ -78,7 +76,7 @@ pub const StatusLineType = enum(u16) {
 
 /// The display to target for status updates (DECSASD).
 pub const StatusDisplay = lib.Enum(
-    lib_target,
+    lib.target,
     &.{
         "main",
         "status_line",
@@ -88,7 +86,7 @@ pub const StatusDisplay = lib.Enum(
 /// The possible modify key formats to ESC[>{a};{b}m
 /// Note: this is not complete, we should add more as we support more
 pub const ModifyKeyFormat = lib.Enum(
-    lib_target,
+    lib.target,
     &.{
         "legacy",
         "cursor_keys",

src/terminal/c/render.zig

@@ -1,7 +1,7 @@
 const std = @import("std");
 const testing = std.testing;
 const Allocator = std.mem.Allocator;
-const lib = @import("../../lib/main.zig");
+const lib = @import("../lib.zig");
 const lib_alloc = @import("../../lib/allocator.zig");
 const CAllocator = lib_alloc.Allocator;
 const colorpkg = @import("../color.zig");

src/terminal/c/terminal.zig

@@ -1,6 +1,6 @@
 const std = @import("std");
 const testing = std.testing;
-const lib = @import("../../lib/main.zig");
+const lib = @import("../lib.zig");
 const lib_alloc = @import("../../lib/allocator.zig");
 const CAllocator = lib_alloc.Allocator;
 const ZigTerminal = @import("../Terminal.zig");

src/terminal/csi.zig

@@ -1,6 +1,4 @@
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 
 /// Modes for the ED CSI command.
 pub const EraseDisplay = enum(u8) {
@@ -38,7 +36,7 @@ pub const TabClear = enum(u8) {
 
 /// Style formats for terminal size reports.
 pub const SizeReportStyle = lib.Enum(
-    lib_target,
+    lib.target,
     &.{
         // XTWINOPS
         "csi_14_t",

src/terminal/device_attributes.zig

@@ -1,11 +1,9 @@
 const std = @import("std");
 const testing = std.testing;
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 
 /// The device attribute request type (CSI c).
-pub const Req = lib.Enum(lib_target, &.{
+pub const Req = lib.Enum(lib.target, &.{
     "primary", // Blank
     "secondary", // >
     "tertiary", // =

src/terminal/device_status.zig

@@ -1,10 +1,8 @@
 const std = @import("std");
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 
 /// The color scheme reported in response to a CSI ? 996 n query.
-pub const ColorScheme = lib.Enum(lib_target, &.{
+pub const ColorScheme = lib.Enum(lib.target, &.{
     "light",
     "dark",
 });

src/terminal/focus.zig

@@ -1,7 +1,5 @@
 const std = @import("std");
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 
 /// Maximum number of bytes that `encode` will write. Any users of this
 /// should be resilient to this changing, so this is always a specific
@@ -10,7 +8,7 @@ pub const max_encode_size = 3;
 
 /// A focus event that can be reported to the application running in the
 /// terminal when focus reporting mode (mode 1004) is enabled.
-pub const Event = lib.Enum(lib_target, &.{
+pub const Event = lib.Enum(lib.target, &.{
     "gained",
     "lost",
 });

src/terminal/formatter.zig

@@ -1,8 +1,6 @@
 const std = @import("std");
-const build_options = @import("terminal_options");
 const assert = @import("../quirks.zig").inlineAssert;
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 const Allocator = std.mem.Allocator;
 const color = @import("color.zig");
 const size = @import("size.zig");
@@ -22,7 +20,7 @@ const Selection = @import("Selection.zig");
 const Style = @import("style.zig").Style;
 
 /// Formats available.
-pub const Format = lib.Enum(lib_target, &.{
+pub const Format = lib.Enum(lib.target, &.{
     // Plain text.
     "plain",
 

src/terminal/lib.zig

@@ -0,0 +1,23 @@
+const std = @import("std");
+const build_options = @import("terminal_options");
+const lib = @import("../lib/main.zig");
+
+/// The target for the terminal lib in particular.
+pub const target: lib.Target = if (build_options.c_abi) .c else .zig;
+
+/// The calling convention to use for C APIs. If we're not building for
+/// C ABI then we use auto which allows our C APIs to be cleanly called
+/// by Zig. This is required because we modify our struct layouts based
+/// on C ABI too.
+pub const calling_conv: std.builtin.CallingConvention = if (build_options.c_abi)
+    .c
+else
+    .auto;
+
+/// Forwarded decls from lib that are used.
+pub const Enum = lib.Enum;
+pub const TaggedUnion = lib.TaggedUnion;
+pub const Struct = lib.Struct;
+pub const String = lib.String;
+pub const checkGhosttyHEnum = lib.checkGhosttyHEnum;
+pub const structSizedFieldFits = lib.structSizedFieldFits;

src/terminal/mouse.zig

@@ -1,11 +1,10 @@
 const std = @import("std");
 const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 
 /// The event types that can be reported for mouse-related activities.
 /// These are all mutually exclusive (hence in a single enum).
-pub const Event = lib.Enum(lib_target, &.{
+pub const Event = lib.Enum(lib.target, &.{
     "none",
     "x10", // 9
     "normal", // 1000
@@ -20,7 +19,7 @@ pub fn eventSendsMotion(event: Event) bool {
 
 /// The format of mouse events when enabled.
 /// These are all mutually exclusive (hence in a single enum).
-pub const Format = lib.Enum(lib_target, &.{
+pub const Format = lib.Enum(lib.target, &.{
     "x10",
     "utf8", // 1005
     "sgr", // 1006

src/terminal/osc.zig

@@ -11,11 +11,11 @@ const build_options = @import("terminal_options");
 const mem = std.mem;
 const assert = @import("../quirks.zig").inlineAssert;
 const Allocator = mem.Allocator;
-const LibEnum = @import("../lib/enum.zig").Enum;
+const lib = @import("lib.zig");
+const LibEnum = lib.Enum;
 const kitty_color = @import("kitty/color.zig");
 const parsers = @import("osc/parsers.zig");
 const encoding = @import("osc/encoding.zig");
-const lib = @import("../lib/main.zig");
 
 pub const color = parsers.color;
 pub const semantic_prompt = parsers.semantic_prompt;
@@ -165,7 +165,7 @@ pub const Command = union(Key) {
     pub const KittyClipboardProtocol = parsers.kitty_clipboard_protocol.OSC;
 
     pub const Key = LibEnum(
-        if (build_options.c_abi) .c else .zig,
+        lib.target,
         // NOTE: Order matters, see LibEnum documentation.
         &.{
             "invalid",

src/terminal/osc/parsers/kitty_text_sizing.zig

@@ -2,27 +2,25 @@
 //! Specification: https://sw.kovidgoyal.net/kitty/text-sizing-protocol/
 
 const std = @import("std");
-const build_options = @import("terminal_options");
 
 const assert = @import("../../../quirks.zig").inlineAssert;
 
 const Parser = @import("../../osc.zig").Parser;
 const Command = @import("../../osc.zig").Command;
 const encoding = @import("../encoding.zig");
-const lib = @import("../../../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("../../lib.zig");
 
 const log = std.log.scoped(.kitty_text_sizing);
 
 pub const max_payload_length = 4096;
 
-pub const VAlign = lib.Enum(lib_target, &.{
+pub const VAlign = lib.Enum(lib.target, &.{
     "top",
     "bottom",
     "center",
 });
 
-pub const HAlign = lib.Enum(lib_target, &.{
+pub const HAlign = lib.Enum(lib.target, &.{
     "left",
     "right",
     "center",

src/terminal/point.zig

@@ -1,18 +1,15 @@
 const std = @import("std");
 const Allocator = std.mem.Allocator;
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
+const lib = @import("lib.zig");
 const size = @import("size.zig");
 
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
-
 /// The possible reference locations for a point. When someone says "(42, 80)"
 /// in the context of a terminal, that could mean multiple things: it is in the
 /// current visible viewport? the current active area of the screen where the
 /// cursor is? the entire scrollback history? etc.
 ///
 /// This tag is used to differentiate those cases.
-pub const Tag = lib.Enum(lib_target, &.{
+pub const Tag = lib.Enum(lib.target, &.{
     // Top-left is part of the active area where a running program can
     // jump the cursor and make changes. The active area is the "editable"
     // part of the screen.
@@ -70,7 +67,7 @@ pub const Point = union(Tag) {
     }
 
     const c_union = lib.TaggedUnion(
-        lib_target,
+        lib.target,
         @This(),
         // Padding: largest variant is Coordinate (u16 + u32 = 6 bytes).
         // Use [2]u64 (16 bytes) for future expansion.

src/terminal/render.zig

@@ -1,11 +1,9 @@
 const std = @import("std");
-const build_options = @import("terminal_options");
 const assert = @import("../quirks.zig").inlineAssert;
 const Allocator = std.mem.Allocator;
 const ArenaAllocator = std.heap.ArenaAllocator;
 const fastmem = @import("../fastmem.zig");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 const color = @import("color.zig");
 const cursor = @import("cursor.zig");
 const highlight = @import("highlight.zig");
@@ -226,7 +224,7 @@ pub const RenderState = struct {
     };
 
     // Dirty state.
-    pub const Dirty = lib.Enum(lib_target, &.{
+    pub const Dirty = lib.Enum(lib.target, &.{
         // Not dirty at all. Can skip rendering if prior state was
         // already rendered.
         "false",

src/terminal/sgr.zig

@@ -1,15 +1,12 @@
 //! SGR (Select Graphic Rendition) attrinvbute parsing and types.
 
 const std = @import("std");
-const build_options = @import("terminal_options");
 const assert = @import("../quirks.zig").inlineAssert;
 const testing = std.testing;
-const lib = @import("../lib/main.zig");
+const lib = @import("lib.zig");
 const color = @import("color.zig");
 const SepList = @import("Parser.zig").Action.CSI.SepList;
 
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
-
 /// Attribute type for SGR
 pub const Attribute = union(Tag) {
     /// Unset all attributes
@@ -81,7 +78,7 @@ pub const Attribute = union(Tag) {
     @"256_fg": u8,
 
     pub const Tag = lib.Enum(
-        lib_target,
+        lib.target,
         &.{
             "unset",
             "unknown",
@@ -158,7 +155,7 @@ pub const Attribute = union(Tag) {
 
     /// C ABI functions.
     const c_union = lib.TaggedUnion(
-        lib_target,
+        lib.target,
         @This(),
         // Padding size for C ABI compatibility.
         // Largest variant is Unknown.C: 2 pointers + 2 usize = 32 bytes on 64-bit.

src/terminal/size_report.zig

@@ -1,11 +1,9 @@
 const std = @import("std");
-const build_options = @import("terminal_options");
-const lib = @import("../lib/main.zig");
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
+const lib = @import("lib.zig");
 const CellCountInt = @import("size.zig").CellCountInt;
 
 /// Output formats for terminal size reports written to the PTY.
-pub const Style = lib.Enum(lib_target, &.{
+pub const Style = lib.Enum(lib.target, &.{
     // In-band size reports (mode 2048)
     "mode_2048",
     // XTWINOPS: report text area size in pixels
@@ -17,7 +15,7 @@ pub const Style = lib.Enum(lib_target, &.{
 });
 
 /// Runtime size values used to encode terminal size reports.
-pub const Size = lib.Struct(lib_target, struct {
+pub const Size = lib.Struct(lib.target, struct {
     /// Terminal row count in cells.
     rows: CellCountInt,
 

src/terminal/stream.zig

@@ -5,7 +5,7 @@ const assert = @import("../quirks.zig").inlineAssert;
 const testing = std.testing;
 const Allocator = std.mem.Allocator;
 const simd = @import("../simd/main.zig");
-const lib = @import("../lib/main.zig");
+const lib = @import("lib.zig");
 const Parser = @import("Parser.zig");
 const ansi = @import("ansi.zig");
 const charsets = @import("charsets.zig");
@@ -29,8 +29,6 @@ const log = std.log.scoped(.stream);
 /// do something else.
 const debug = false;
 
-const lib_target: lib.Target = if (build_options.c_abi) .c else .zig;
-
 /// The possible actions that can be emitted by the Stream
 /// function for handling.
 pub const Action = union(Key) {
@@ -129,7 +127,7 @@ pub const Action = union(Key) {
     semantic_prompt: SemanticPrompt,
 
     pub const Key = lib.Enum(
-        lib_target,
+        lib.target,
         &.{
             "print",
             "print_repeat",
@@ -229,7 +227,7 @@ pub const Action = union(Key) {
 
     /// C ABI functions.
     const c_union = lib.TaggedUnion(
-        lib_target,
+        lib.target,
         @This(),
         // TODO: Before shipping an ABI-compatible libghostty, verify this.
         // This was just arbitrarily chosen for now.
@@ -254,7 +252,7 @@ pub const Action = union(Key) {
         }
     };
 
-    pub const InvokeCharset = lib.Struct(lib_target, struct {
+    pub const InvokeCharset = lib.Struct(lib.target, struct {
         bank: charsets.ActiveSlot,
         charset: charsets.Slots,
         locking: bool,
@@ -384,7 +382,7 @@ pub const Action = union(Key) {
         }
     };
 
-    pub const ConfigureCharset = lib.Struct(lib_target, struct {
+    pub const ConfigureCharset = lib.Struct(lib.target, struct {
         slot: charsets.Slots,
         charset: charsets.Charset,
     });