Revamp CURL integration. Exclude it from APPLE

deps/CURL/CURL.cmake

@@ -48,11 +48,13 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
   )
 endif ()
 
-if (BUILD_SHARED_LIBS)
-  set(_curl_static OFF)
-else()
-  set(_curl_static ON)
-endif()
+set(_patch_command "")
+if (UNIX AND NOT APPLE)
+  # On non-apple UNIX platforms, finding the location of OpenSSL certificates is necessary at runtime, as there is no standard location usable across platforms.
+  # The OPENSSL_CERT_OVERRIDE flag is understood by PrusaSlicer and will trigger the search of certificates at initial application launch. 
+  # Then ask the user for consent about the correctness of the found location.
+  set (_patch_command echo set_target_properties(CURL::libcurl PROPERTIES INTERFACE_COMPILE_DEFINITIONS OPENSSL_CERT_OVERRIDE) >> CMake/curl-config.cmake.in)
+endif ()
 
 prusaslicer_add_cmake_project(CURL
   # GIT_REPOSITORY      https://github.com/curl/curl.git
@@ -62,10 +64,10 @@ prusaslicer_add_cmake_project(CURL
   DEPENDS             ${ZLIB_PKG}
   # PATCH_COMMAND       ${GIT_EXECUTABLE} checkout -f -- . && git clean -df && 
   #                     ${GIT_EXECUTABLE} apply --whitespace=fix ${CMAKE_CURRENT_LIST_DIR}/curl-mods.patch
+  PATCH_COMMAND       "${_patch_command}"
   CMAKE_ARGS
     -DBUILD_TESTING:BOOL=OFF
     -DCMAKE_POSITION_INDEPENDENT_CODE=ON
-    -DCURL_STATICLIB=${_curl_static}
     ${_curl_platform_flags}
 )