Fix check against BUILD_ALT_BENCH that was always defined as OFF

diff --git a/test/benchmarks/CMakeLists.txt b/test/benchmarks/CMakeLists.txt
index e332a5165aef749b4fb2ae8a16ae61c130fad7e3..8cf96d8c19f874f8231efbc02664c63dc0e5eba4 100644 (file)
--- a/test/benchmarks/CMakeLists.txt
+++ b/test/benchmarks/CMakeLists.txt
@@ -114,7 +114,7 @@ if(WITH_BENCHMARK_APPS)
 
     add_executable(benchmark_zlib_apps ${BENCH_APP_SRCS})
 
-    if(DEFINED BUILD_ALT_BENCH)
+    if(BUILD_ALT_BENCH)
         set(ZLIB_ALT_LIB "libz.a" CACHE FILEPATH "Optional alternative zlib implementation (defaults to stock zlib)")
         add_executable(benchmark_zlib_apps_alt ${BENCH_APP_SRCS})
         target_link_libraries(benchmark_zlib_apps_alt ${PNG_STATIC_LIBRARY} ${ZLIB_ALT_LIB} benchmark::benchmark)