diff --git a/lib/base64.c b/lib/base64.c
index 8957eaf416..3e819d2326 100644
--- a/lib/base64.c
+++ b/lib/base64.c
@@ -32,7 +32,7 @@
   !defined(CURL_DISABLE_POP3) || \
   !defined(CURL_DISABLE_IMAP) || \
   !defined(CURL_DISABLE_DIGEST_AUTH) || \
-  !defined(CURL_DISABLE_DOH) || defined(USE_SSL) || defined(BUILDING_CURL)
+  !defined(CURL_DISABLE_DOH) || defined(USE_SSL) || !defined(BUILDING_LIBCURL)
 #include "curl/curl.h"
 #include "warnless.h"
 #include "curl_base64.h"
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9e62d4f354..d0d5980c35 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -22,7 +22,6 @@
 #
 ###########################################################################
 set(EXE_NAME curl)
-set_property(DIRECTORY APPEND PROPERTY COMPILE_DEFINITIONS "BUILDING_CURL")
 
 set(_curl_cfiles_gen "")
 set(_curl_hfiles_gen "")
diff --git a/src/Makefile.am b/src/Makefile.am
index f45920b16f..a97b0bcbee 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -51,7 +51,6 @@ bin_PROGRAMS = curl
 if USE_CPPFLAG_CURL_STATICLIB
 AM_CPPFLAGS += -DCURL_STATICLIB
 endif
-AM_CPPFLAGS += -DBUILDING_CURL
 
 AM_LDFLAGS =
 if USE_UNICODE