Propagate CMAKE_BUILD_TYPE to external projects (#1763)

Ensures external dependencies like Google Benchmark inherit the main project's build type, preventing unoptimized debug builds and timing warnings.

Fixes #1761

Author: leetcodez

cmake/modules/AddClad.cmake

@@ -249,6 +249,7 @@ function(clad_externalproject_add NAME)
     ${FORWARDED_ARGS}
     CMAKE_ARGS
       -G "${CMAKE_GENERATOR}"
+      -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
       -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
       -DCMAKE_C_FLAGS=${C_FLAGS_EXT}
       -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}