[make] replace echo commands with $(info)

Seems to result in less forks since it doesn't need to run an echo
binary.

make/macros.mk

@@ -32,8 +32,8 @@ endef
 
 # generate a header file at $1 with an expanded variable in $2
 define MAKECONFIGHEADER
+	$(info generating $1) \
 	$(MKDIR); \
-	echo generating $1; \
 	rm -f $1.tmp; \
 	LDEF=`echo $1 | tr '/\\.-' '_' | sed "s/C++/CPP/g;s/c++/cpp/g"`; \
 	echo \#ifndef __$${LDEF}_H > $1.tmp; \