fix(win): Embed manifest in OIIO .exes to enable long path handling

Signed-off-by: Nathan Rusch <nrusch@github>

Author: nrusch

src/cmake/fancy_add_executable.cmake

@@ -44,6 +44,12 @@ macro (fancy_add_executable)
     check_is_enabled (${_target_NAME} _target_NAME_enabled)
     if (_target_NAME_enabled)
         add_executable (${_target_NAME} ${_target_SRC})
+        if (WIN32)
+            # Disable default manifest generation to avoid conflicts.
+            target_link_options(${_target_NAME} PRIVATE "/MANIFEST:NO")
+            # Include Windows resource file, which will in turn embed our exe manifest.
+            target_sources(${_target_NAME} PRIVATE "${PROJECT_SOURCE_DIR}/src/windows/oiio_exe.rc")
+        endif ()
         target_include_directories (${_target_NAME} PRIVATE ${_target_INCLUDE_DIRS})
         target_include_directories (${_target_NAME} SYSTEM PRIVATE ${_target_SYSTEM_INCLUDE_DIRS})
         target_compile_definitions (${_target_NAME} PRIVATE

src/windows/oiio_exe.manifest

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
+  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
+    <security>
+      <requestedPrivileges>
+        <requestedExecutionLevel level="asInvoker" uiAccess="false"></requestedExecutionLevel>
+      </requestedPrivileges>
+    </security>
+  </trustInfo>
+  <application xmlns="urn:schemas-microsoft-com:asm.v3">
+    <windowsSettings xmlns:ws2="http://schemas.microsoft.com/SMI/2016/WindowsSettings">
+        <ws2:longPathAware>true</ws2:longPathAware>
+    </windowsSettings>
+  </application>
+</assembly>

src/windows/oiio_exe.rc

@@ -0,0 +1,6 @@
+// Resource script for OIIO EXEs.
+
+// The value is invariant, so should be safe to hardcode, but we could replace
+// 24 with `RT_MANIFEST` by adding `#include "winres.h"` first.
+// Reference: https://learn.microsoft.com/en-us/windows/win32/menurc/user-defined-resource
+1 24 "oiio_exe.manifest"