ci: fix windows cgo compiler error (#15046)

x/imagegen/mlx/CMakeLists.txt

@@ -101,12 +101,25 @@ file(COPY ${_mlx_c_hdrs} DESTINATION "${CMAKE_SOURCE_DIR}/x/mlxrunner/mlx/includ
 # Regenerate Go/C shim wrappers from the (possibly updated) headers.
 find_program(GO_EXECUTABLE go REQUIRED)
 message(STATUS "Regenerating MLX Go wrappers")
+
+# Go's cgo splits CC on whitespace, so a CC like "C:/Program Files/…/cl.exe"
+# (set by cmake on Windows) breaks with "C:/Program" not found.  Clear CC
+# when it contains spaces so cgo falls back to its default (gcc).
+if(WIN32 AND "$ENV{CC}" MATCHES " ")
+    set(_SAVE_CC "$ENV{CC}")
+    set(ENV{CC} "")
+endif()
+
 execute_process(
     COMMAND ${GO_EXECUTABLE} generate ./x/...
     WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
     COMMAND_ERROR_IS_FATAL ANY
 )
 
+if(DEFINED _SAVE_CC)
+    set(ENV{CC} "${_SAVE_CC}")
+endif()
+
 # For local dev builds, override MLX_VERSION with git describe output
 if(TARGET mlx_version AND DEFINED FETCHCONTENT_SOURCE_DIR_MLX)
     execute_process(