How to change VAR name without getting the undeclared error after 'make install'?

My configure.in file has:

VAR=yo
AC_SUBST(VAR)

Makefile.am has:

bin_PROGRAMS = hello
hello_SOURCES = hello.c 
hello_CFLAGS =-DVAR=@VAR@

C file is:

#include <stdio.h>
int main()
{
    printf("%s\n",VAR);
    return 0;
}

When I do 'make install' there is error

Making install in src
make[1]: Entering directory `/home/albertpod/hello/src'
if gcc -DPACKAGE_NAME=\"hello\" -DPACKAGE_TARNAME=\"hello\" -DPACKAGE_VERSION=\"1.0\" -DPACKAGE_STRING=\"hello\ 1.0\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPACKAGE=\"hello\" -DVERSION=\"1.0\" -I. -I.    -DVAR=yo -g -O2 -MT hello-hello.o -MD -MP -MF ".deps/hello-hello.Tpo" -c -o hello-hello.o `test -f 'hello.c' || echo './'`hello.c; \
    then mv -f ".deps/hello-hello.Tpo" ".deps/hello-hello.Po"; else rm -f ".deps/hello-hello.Tpo"; exit 1; fi
hello.c: In function ‘main’:
hello.c:8:13: error: ‘yo’ undeclared (first use in this function)
hello.c:8:13: note: each undeclared identifier is reported only once for each function it appears in
make[1]: *** [hello-hello.o] Error 1
make[1]: Leaving directory `/home/albertpod/hello/src'
make: *** [install-recursive] Error 1

So name of VAR becomes yo, but it is undeclared. My goal is to print yo, but how to solve this case?

via Chebli Mohamed