diff --git a/glfw/build.zig b/glfw/build.zig
index e03af9b6..0adcaf75 100644
--- a/glfw/build.zig
+++ b/glfw/build.zig
@@ -61,7 +61,7 @@ fn buildLibrary(b: *Builder, step: *std.build.LibExeObjStep, options: Options) *
     // TODO(build-system): https://github.com/hexops/mach/issues/229#issuecomment-1100958939
     ensureDependencySubmodule(b.allocator, "upstream") catch unreachable;
 
-    const main_abs = std.fs.path.join(b.allocator, &.{ thisDir(), "src/main.zig" }) catch unreachable;
+    const main_abs = std.fs.path.join(b.allocator, &.{ (comptime thisDir()), "src/main.zig" }) catch unreachable;
     const lib = b.addStaticLibrary("glfw", main_abs);
     lib.setBuildMode(step.build_mode);
     lib.setTarget(step.target);
@@ -69,16 +69,16 @@ fn buildLibrary(b: *Builder, step: *std.build.LibExeObjStep, options: Options) *
     // TODO(build-system): pass system SDK options through
     system_sdk.include(b, step, .{});
     const target = (std.zig.system.NativeTargetInfo.detect(b.allocator, step.target) catch unreachable).target;
-    const include_glfw_src = "-I" ++ thisDir() ++ "/upstream/glfw/src";
+    const include_glfw_src = "-I" ++ (comptime thisDir()) ++ "/upstream/glfw/src";
     switch (target.os.tag) {
         .windows => lib.addCSourceFiles(&.{
-            thisDir() ++ "/src/sources_all.c",
-            thisDir() ++ "/src/sources_windows.c",
+            (comptime thisDir()) ++ "/src/sources_all.c",
+            (comptime thisDir()) ++ "/src/sources_windows.c",
         }, &.{ "-D_GLFW_WIN32", include_glfw_src }),
         .macos => lib.addCSourceFiles(&.{
-            thisDir() ++ "/src/sources_all.c",
-            thisDir() ++ "/src/sources_macos.m",
-            thisDir() ++ "/src/sources_macos.c",
+            (comptime thisDir()) ++ "/src/sources_all.c",
+            (comptime thisDir()) ++ "/src/sources_macos.m",
+            (comptime thisDir()) ++ "/src/sources_macos.c",
         }, &.{ "-D_GLFW_COCOA", include_glfw_src }),
         else => {
             // TODO(future): for now, Linux must be built with glibc, not musl:
@@ -92,17 +92,17 @@ fn buildLibrary(b: *Builder, step: *std.build.LibExeObjStep, options: Options) *
 
             var sources = std.ArrayList([]const u8).init(b.allocator);
             var flags = std.ArrayList([]const u8).init(b.allocator);
-            sources.append(thisDir() ++ "/src/sources_all.c") catch unreachable;
-            sources.append(thisDir() ++ "/src/sources_linux.c") catch unreachable;
+            sources.append((comptime thisDir()) ++ "/src/sources_all.c") catch unreachable;
+            sources.append((comptime thisDir()) ++ "/src/sources_linux.c") catch unreachable;
             if (options.x11) {
-                sources.append(thisDir() ++ "/src/sources_linux_x11.c") catch unreachable;
+                sources.append((comptime thisDir()) ++ "/src/sources_linux_x11.c") catch unreachable;
                 flags.append("-D_GLFW_X11") catch unreachable;
             }
             if (options.wayland) {
-                sources.append(thisDir() ++ "/src/sources_linux_wayland.c") catch unreachable;
+                sources.append((comptime thisDir()) ++ "/src/sources_linux_wayland.c") catch unreachable;
                 flags.append("-D_GLFW_WAYLAND") catch unreachable;
             }
-            flags.append("-I" ++ thisDir() ++ "/upstream/glfw/src") catch unreachable;
+            flags.append("-I" ++ (comptime thisDir()) ++ "/upstream/glfw/src") catch unreachable;
 
             lib.addCSourceFiles(sources.items, flags.items);
         },
@@ -117,7 +117,7 @@ fn ensureDependencySubmodule(allocator: std.mem.Allocator, path: []const u8) !vo
         if (std.mem.eql(u8, no_ensure_submodules, "true")) return;
     } else |_| {}
     var child = std.ChildProcess.init(&.{ "git", "submodule", "update", "--init", path }, allocator);
-    child.cwd = thisDir();
+    child.cwd = (comptime thisDir());
     child.stderr = std.io.getStdErr();
     child.stdout = std.io.getStdOut();
 
@@ -129,11 +129,11 @@ fn thisDir() []const u8 {
 }
 
 fn linkGLFWDependencies(b: *Builder, step: *std.build.LibExeObjStep, options: Options) void {
-    const include_dir = std.fs.path.join(b.allocator, &.{ thisDir(), "upstream/glfw/include" }) catch unreachable;
+    const include_dir = std.fs.path.join(b.allocator, &.{ (comptime thisDir()), "upstream/glfw/include" }) catch unreachable;
     defer b.allocator.free(include_dir);
     step.addIncludeDir(include_dir);
 
-    const vulkan_include_dir = std.fs.path.join(b.allocator, &.{ thisDir(), "upstream/vulkan_headers/include" }) catch unreachable;
+    const vulkan_include_dir = std.fs.path.join(b.allocator, &.{ (comptime thisDir()), "upstream/vulkan_headers/include" }) catch unreachable;
     defer b.allocator.free(vulkan_include_dir);
     step.addIncludeDir(vulkan_include_dir);
 
diff --git a/glfw/src/Joystick.zig b/glfw/src/Joystick.zig
index 68aaa01f..aef52c2e 100644
--- a/glfw/src/Joystick.zig
+++ b/glfw/src/Joystick.zig
@@ -255,7 +255,7 @@ pub inline fn getName(self: Joystick) error{PlatformError}!?[:0]const u8 {
         else => unreachable,
     };
     return if (name_opt) |name|
-        std.mem.span(name)
+        std.mem.span(@ptrCast([*:0]const u8, name))
     else
         null;
 }
@@ -297,7 +297,7 @@ pub inline fn getGUID(self: Joystick) error{PlatformError}!?[:0]const u8 {
         else => unreachable,
     };
     return if (guid_opt) |guid|
-        std.mem.span(guid)
+        std.mem.span(@ptrCast([*:0]const u8, guid))
     else
         null;
 }
@@ -490,7 +490,7 @@ pub inline fn getGamepadName(self: Joystick) ?[:0]const u8 {
         else => unreachable,
     };
     return if (name_opt) |name|
-        std.mem.span(name)
+        std.mem.span(@ptrCast([*:0]const u8, name))
     else
         null;
 }
@@ -603,7 +603,8 @@ test "setUserPointer_syntax" {
     const joystick = glfw.Joystick{ .jid = .one };
 
     // Must be called from joystick callback, we cannot test it.
-    _ = joystick.setUserPointer;
+    _ = joystick;
+    _ = setUserPointer;
 }
 
 test "getUserPointer_syntax" {
@@ -614,7 +615,8 @@ test "getUserPointer_syntax" {
     const joystick = glfw.Joystick{ .jid = .one };
 
     // Must be called from joystick callback, we cannot test it.
-    _ = joystick.getUserPointer;
+    _ = joystick;
+    _ = getUserPointer;
 }
 
 test "setCallback" {
diff --git a/glfw/src/Monitor.zig b/glfw/src/Monitor.zig
index a0f02c47..82631b27 100644
--- a/glfw/src/Monitor.zig
+++ b/glfw/src/Monitor.zig
@@ -164,7 +164,7 @@ pub inline fn getContentScale(self: Monitor) error{PlatformError}!ContentScale {
 /// see also: monitor_properties
 pub inline fn getName(self: Monitor) [*:0]const u8 {
     internal_debug.assertInitialized();
-    if (c.glfwGetMonitorName(self.handle)) |name| return name;
+    if (c.glfwGetMonitorName(self.handle)) |name| return @ptrCast([*:0]const u8, name);
     getError() catch |err| return switch (err) {
         Error.NotInitialized => unreachable,
         else => unreachable,
@@ -239,7 +239,7 @@ pub inline fn getVideoModes(self: Monitor, allocator: mem.Allocator) (mem.Alloca
         const slice = try allocator.alloc(VideoMode, @intCast(u32, count));
         var i: u32 = 0;
         while (i < count) : (i += 1) {
-            slice[i] = VideoMode{ .handle = modes[i] };
+            slice[i] = VideoMode{ .handle = @ptrCast([*c]const c.GLFWvidmode, modes)[i] };
         }
         return slice;
     }
@@ -390,7 +390,7 @@ pub inline fn getAll(allocator: mem.Allocator) mem.Allocator.Error![]Monitor {
         const slice = try allocator.alloc(Monitor, @intCast(u32, count));
         var i: u32 = 0;
         while (i < count) : (i += 1) {
-            slice[i] = Monitor{ .handle = monitors[i].? };
+            slice[i] = Monitor{ .handle = @ptrCast([*c]const ?*c.GLFWmonitor, monitors)[i].? };
         }
         return slice;
     }
diff --git a/glfw/src/clipboard.zig b/glfw/src/clipboard.zig
index 8a4bf3df..9c7c0560 100644
--- a/glfw/src/clipboard.zig
+++ b/glfw/src/clipboard.zig
@@ -48,7 +48,7 @@ pub inline fn setClipboardString(value: [*:0]const u8) error{PlatformError}!void
 /// see also: clipboard, glfwSetClipboardString
 pub inline fn getClipboardString() error{ FormatUnavailable, PlatformError }![:0]const u8 {
     internal_debug.assertInitialized();
-    if (c.glfwGetClipboardString(null)) |c_str| return std.mem.span(c_str);
+    if (c.glfwGetClipboardString(null)) |c_str| return std.mem.span(@ptrCast([*:0]const u8, c_str));
     getError() catch |err| return switch (err) {
         Error.NotInitialized => unreachable,
         Error.FormatUnavailable, Error.PlatformError => |e| e,
diff --git a/glfw/src/key.zig b/glfw/src/key.zig
index 52f02f15..d274378b 100644
--- a/glfw/src/key.zig
+++ b/glfw/src/key.zig
@@ -223,7 +223,7 @@ pub const Key = enum(c_int) {
             else => unreachable,
         };
         return if (name_opt) |name|
-            std.mem.span(name)
+            std.mem.span(@ptrCast([*:0]const u8, name))
         else
             null;
     }
diff --git a/glfw/src/main.zig b/glfw/src/main.zig
index e2084a77..e8849979 100644
--- a/glfw/src/main.zig
+++ b/glfw/src/main.zig
@@ -288,7 +288,7 @@ fn initHint(hint: InitHint, value: anytype) void {
 ///
 /// thread_safety: This function may be called from any thread.
 pub inline fn getVersionString() [:0]const u8 {
-    return std.mem.span(c.glfwGetVersionString());
+    return std.mem.span(@ptrCast([*:0]const u8, c.glfwGetVersionString()));
 }
 
 /// Returns the currently selected platform.
diff --git a/glfw/src/opengl.zig b/glfw/src/opengl.zig
index 125aaf70..10b0e361 100644
--- a/glfw/src/opengl.zig
+++ b/glfw/src/opengl.zig
@@ -137,7 +137,7 @@ pub inline fn extensionSupported(extension: [:0]const u8) error{ NoCurrentContex
     std.debug.assert(extension.len != 0);
     std.debug.assert(extension[0] != 0);
 
-    const supported = c.glfwExtensionSupported(extension);
+    const supported = c.glfwExtensionSupported(extension.ptr);
     getError() catch |err| return switch (err) {
         Error.NoCurrentContext, Error.PlatformError => |e| e,
         Error.NotInitialized => unreachable,
@@ -147,12 +147,13 @@ pub inline fn extensionSupported(extension: [:0]const u8) error{ NoCurrentContex
     return supported == c.GLFW_TRUE;
 }
 
+const builtin = @import("builtin");
 /// Client API function pointer type.
 ///
 /// Generic function pointer used for returning client API function pointers.
 ///
 /// see also: context_glext, glfwGetProcAddress
-pub const GLProc = fn () callconv(.C) void;
+pub const GLProc = if (builtin.zig_backend == .stage1 or builtin.zig_backend == .other) fn () callconv(.C) void else *const fn () callconv(.C) void;
 
 /// Returns the address of the specified function for the current context.
 ///
@@ -197,7 +198,7 @@ test "makeContextCurrent" {
     try glfw.init(.{});
     defer glfw.terminate();
 
-    const window = glfw.Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
+    const window = Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
         // return without fail, because most of our CI environments are headless / we cannot open
         // windows on them.
         std.debug.print("note: failed to create window: {}\n", .{err});
@@ -222,7 +223,7 @@ test "swapInterval" {
     try glfw.init(.{});
     defer glfw.terminate();
 
-    const window = glfw.Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
+    const window = Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
         // return without fail, because most of our CI environments are headless / we cannot open
         // windows on them.
         std.debug.print("note: failed to create window: {}\n", .{err});
@@ -239,7 +240,7 @@ test "getProcAddress" {
     try glfw.init(.{});
     defer glfw.terminate();
 
-    const window = glfw.Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
+    const window = Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
         // return without fail, because most of our CI environments are headless / we cannot open
         // windows on them.
         std.debug.print("note: failed to create window: {}\n", .{err});
@@ -256,7 +257,7 @@ test "extensionSupported" {
     try glfw.init(.{});
     defer glfw.terminate();
 
-    const window = glfw.Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
+    const window = Window.create(640, 480, "Hello, Zig!", null, null, .{}) catch |err| {
         // return without fail, because most of our CI environments are headless / we cannot open
         // windows on them.
         std.debug.print("note: failed to create window: {}\n", .{err});