--- CMakeLists.txt.orig	2026-08-01 23:39:17 UTC
+++ CMakeLists.txt
@@ -195,6 +195,7 @@ ExternalProject_Add(zlib
     -DBUILD_SHARED_LIBS=OFF
     -DZLIB_BUILD_EXAMPLES=OFF
   BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --parallel ${SUBJOBS}
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E env DESTDIR= ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
 )
 
 # zstd
@@ -214,6 +215,7 @@ ExternalProject_Add(zstd
     -DZSTD_BUILD_CONTRIB=OFF
     -DZSTD_BUILD_TESTS=OFF
   BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --parallel ${SUBJOBS}
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E env DESTDIR= ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
 )
 
 # brotli
@@ -234,7 +236,7 @@ ExternalProject_Add(brotli
     -DBROTLI_BUILD_TOOLS=OFF
     -DCMAKE_MACOSX_BUNDLE=OFF
   BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --parallel ${SUBJOBS}
-  INSTALL_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E env DESTDIR= ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
 )
 
 # boringssl
@@ -270,7 +272,7 @@ ExternalProject_Add(boringssl
   PATCH_COMMAND ${PATCH_EXE} -p1 -i "${_boringssl_patch_file}"
   CMAKE_ARGS ${_boringssl_cmake_args}
   BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target ssl crypto --parallel ${SUBJOBS}
-  INSTALL_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E env DESTDIR= ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
 )
 
 ExternalProject_Get_Property(boringssl source_dir binary_dir)
@@ -308,7 +310,7 @@ ExternalProject_Add(nghttp2
     -DENABLE_DOC=OFF
     -DBUILD_TESTING=OFF
   BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --parallel ${SUBJOBS}
-  INSTALL_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E env DESTDIR= ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
 )
 
 # nghttp3
@@ -330,7 +332,7 @@ ExternalProject_Add(nghttp3
     -DBUILD_TESTING=OFF
   BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --parallel ${SUBJOBS}
   INSTALL_COMMAND
-    ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
+    ${CMAKE_COMMAND} -E env DESTDIR= ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
     COMMAND ${CMAKE_COMMAND} -E copy_if_different
       <SOURCE_DIR>/lib/includes/nghttp3/nghttp3.h
       <INSTALL_DIR>/include/nghttp3/nghttp3.h
@@ -370,7 +372,7 @@ ExternalProject_Add(ngtcp2
     -DBORINGSSL_INCLUDE_DIR=${BORINGSSL_INCLUDE_DIR}
     ${_ngtcp2_boringssl_libs_arg}
   BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --parallel ${SUBJOBS}
-  INSTALL_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E env DESTDIR= ${CMAKE_COMMAND} --build <BINARY_DIR> --config Release --target install --parallel ${SUBJOBS}
 )
 
 # libidn2