add a comment for host-builds similar to target-builds

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>

Makefile

@@ -194,6 +194,7 @@ $(TARGET_BUILD_DIR)/%.o: CC = $(TARGET_CC)
 $(TARGET_BUILD_DIR)/%.o: CPPFLAGS += $(TARGET_CPPFLAGS)
 $(TARGET_BUILD_DIR)/%.o: CFLAGS += $(TARGET_CFLAGS)
 
+# Override CC for host-builds
 $(HOST_BUILD_DIR)/%.o: CFLAGS += $(HOST_CFLAGS)
 $(HOST_BUILD_DIR)/%.o: CXXFLAGS += $(HOST_CXXFLAGS)
 bin/pimpconv$(EXE_EXT): CC = $(CXX)