fix: print cmake error output when curl build fails

The curl cmake configure has been failing on CI since PR #173 but the
actual error was hidden — captured in a variable but never printed.
This matches the error reporting pattern used by libzip.cmake and
arrow.cmake.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: timosachsenberg

libraries.cmake/curl.cmake

@@ -60,7 +60,10 @@ file(APPEND ${LOGFILE} ${_CURL_CMAKE_OUT})
 file(APPEND ${LOGFILE} ${_CURL_CMAKE_ERR})
 
 if (NOT _CURL_CMAKE_SUCCESS EQUAL 0)
-  message(FATAL_ERROR "Generating curl build system .. failed")
+  message(STATUS "Generating curl build system .. failed")
+  message(STATUS "Output: ${_CURL_CMAKE_OUT}")
+  message(STATUS "Error: ${_CURL_CMAKE_ERR}")
+  message(FATAL_ERROR "curl configuration failed. Check the log file for details: ${LOGFILE}")
 else()
   message(STATUS "Generating curl build system .. done")
 endif()
@@ -84,7 +87,10 @@ file(APPEND ${LOGFILE} ${_CURL_BUILD_OUT})
 file(APPEND ${LOGFILE} ${_CURL_BUILD_ERR})
 
 if (NOT _CURL_BUILD_SUCCESS EQUAL 0)
-  message(FATAL_ERROR "Building curl (Release) .. failed")
+  message(STATUS "Building curl (Release) .. failed")
+  message(STATUS "Output: ${_CURL_BUILD_OUT}")
+  message(STATUS "Error: ${_CURL_BUILD_ERR}")
+  message(FATAL_ERROR "curl build failed. Check the log file for details: ${LOGFILE}")
 else()
   message(STATUS "Building curl (Release) .. done")
 endif()