cmake: respect `GNUTLS_CFLAGS` when detected via `pkg-config`

Closes #16242

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8ec0792c31ab0ac665123082bb6aa2c739ebcebf..38d7b67478f3e6703326b623af0c07641bd3e8bf 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -838,6 +838,10 @@ if(CURL_USE_GNUTLS)
     pkg_check_modules(GNUTLS "gnutls")
     if(GNUTLS_FOUND)
       set(GNUTLS_LIBRARIES ${GNUTLS_LINK_LIBRARIES})
+      string(REPLACE ";" " " GNUTLS_CFLAGS "${GNUTLS_CFLAGS}")
+      if(GNUTLS_CFLAGS)
+        string(APPEND CMAKE_C_FLAGS " ${GNUTLS_CFLAGS}")
+      endif()
     endif()
   endif()
   if(NOT GNUTLS_FOUND)