FindUSD: invert regex to support alpha 25.05 versions

Author: davvid

cmake/modules/FindUSD.cmake

@@ -78,12 +78,12 @@ if(USD_INCLUDE_DIR AND EXISTS "${USD_INCLUDE_DIR}/pxr/pxr.h")
     # Detect whether PXR_USE_INTERNAL_BOOST_PYTHON is explicitly enabled
     set(USD_USE_INTERNAL_BOOST_PYTHON ON CACHE INTERNAL "")
     string(REGEX MATCH
-        "#if +1[^\n]*\n[ \t]*#define +PXR_USE_INTERNAL_BOOST_PYTHON"
+        "#if +0[^\n]*\n[ \t]*#define +PXR_USE_INTERNAL_BOOST_PYTHON"
         _use_internal_boost_python "${_pxr_header}")
 
     # Use external Boost dependencies if USD version is less than 0.25.5, and
     # if internal Boost.Python is not explicitly enabled
-    if (USD_VERSION VERSION_LESS "0.25.5" AND NOT _use_internal_boost_python)
+    if (USD_VERSION VERSION_LESS "0.25.5" OR _use_internal_boost_python)
         set(USD_USE_INTERNAL_BOOST_PYTHON OFF CACHE INTERNAL "")
         list(APPEND USD_DEPENDENCIES "Boost::boost")
         if (BUILD_PYTHON_BINDINGS)