ENH: seet CURL_CA_PATH to none for macOS, to avoid an error in cmake configure...

ENH: seet CURL_CA_PATH to none for macOS, to avoid an error in cmake configure if a ca path is automatically found (openssl is not enabled for macos, the native ssl is used instead)

SuperBuild/CMake/External_curl.cmake

@@ -32,11 +32,15 @@ if(NOT APPLE AND NOT WIN32)
   list(APPEND CURL_SB_CONFIG
     -DCMAKE_USE_OPENSSL:BOOL=ON
     -DCMAKE_C_FLAGS:STRING=-fPIC)
+# Set CURL_CA_PATH to none because openssl in not enabled and CMake generation will fail if 
+# a CA path is found in auto mode.
 elseif(APPLE)
   list(APPEND CURL_SB_CONFIG
     -DCMAKE_USE_DARWINSSL:BOOL=ON
     -DHAVE_LIBNETWORK:STRING=0
-    -DCMAKE_C_FLAGS:STRING=-fPIC)
+    -DCMAKE_C_FLAGS:STRING=-fPIC
+    -DCURL_CA_PATH:STRING=none)
+
 elseif(WIN32)
   list(APPEND CURL_SB_CONFIG
     -DCMAKE_USE_WINSSL:BOOL=ON