CMake: add CURL_ENABLE_EXPORT_TARGET option

install(EXPORT ...) causes trouble when embedding curl dependencies
which don't provide install(EXPORT ...) targets (e.g libressl and
nghttp2) with cmake's add_subdirectory.

Reviewed-by: Jakub Zakrzewski
Closes #7060

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 63944877a99b4ae571fbe5d44b88bd978791e4e2..0e06f1bbb56216a00f8901fbba45d73c5139bba1 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -191,6 +191,9 @@ mark_as_advanced(CURL_DISABLE_GOPHER)
 option(CURL_DISABLE_MQTT "to disable MQTT" OFF)
 mark_as_advanced(CURL_DISABLE_MQTT)
 
+option(CURL_ENABLE_EXPORT_TARGET "to enable cmake export target" ON)
+mark_as_advanced(CURL_ENABLE_EXPORT_TARGET)
+
 if(HTTP_ONLY)
   set(CURL_DISABLE_DICT ON)
   set(CURL_DISABLE_FILE ON)
@@ -1561,11 +1564,13 @@ configure_package_config_file(CMake/curl-config.cmake.in
         INSTALL_DESTINATION ${CURL_INSTALL_CMAKE_DIR}
 )
 
-install(
-        EXPORT "${TARGETS_EXPORT_NAME}"
-        NAMESPACE "${PROJECT_NAME}::"
-        DESTINATION ${CURL_INSTALL_CMAKE_DIR}
-)
+if(CURL_ENABLE_EXPORT_TARGET)
+  install(
+          EXPORT "${TARGETS_EXPORT_NAME}"
+          NAMESPACE "${PROJECT_NAME}::"
+          DESTINATION ${CURL_INSTALL_CMAKE_DIR}
+  )
+endif()
 
 install(
         FILES ${version_config} ${project_config}