diff --git a/absl/debugging/internal/elf_mem_image.h b/absl/debugging/internal/elf_mem_image.h
index 99b37580..d84200db 100644
--- a/absl/debugging/internal/elf_mem_image.h
+++ b/absl/debugging/internal/elf_mem_image.h
@@ -34,7 +34,7 @@
 #define ABSL_HAVE_ELF_MEM_IMAGE 1
 #endif
 
-#if ABSL_HAVE_ELF_MEM_IMAGE
+#ifdef ABSL_HAVE_ELF_MEM_IMAGE
 
 #include <link.h>  // for ElfW