[CMake] enable install C API objects (#8077)

cmake/modules/AddCIRCT.cmake

@@ -14,6 +14,9 @@ function(add_circt_public_c_api_library name)
   add_mlir_public_c_api_library(${ARGV} DISABLE_INSTALL)
   add_dependencies(circt-capi ${name})
   add_circt_library_install(${name})
+  if(TARGET "obj.${name}" AND MLIR_INSTALL_AGGREGATE_OBJECTS)
+    add_circt_library_install(obj.${name})
+  endif()
 endfunction()
 
 # Additional parameters are forwarded to tablegen.

lib/Bindings/Python/CMakeLists.txt

@@ -24,6 +24,9 @@ set(PYTHON_BINDINGS_SOURCES
   SeqModule.cpp
   SupportModule.cpp
   SVModule.cpp
+  # Headers must be included explicitly so they are installed.
+  CIRCTModules.h
+  PybindUtils.h
 )
 
 set(PYTHON_BINDINGS_LINK_LIBS