| In my configure.in file, I was doing:
|
| dnl Check for ANSI C exit success/failure values.
| AC_EGREP_CPP(yes, [dnl
| #include <stdlib.h>
| #ifdef EXIT_SUCCESS
| yes
| #endif], AC_DEFINE(HAVE_EXIT_SUCCESS))
|
| and the resulting output in 2.13 was:
|
| cat > conftest.$ac_ext <<EOF
| #line 5424 "configure"
| #include "confdefs.h"
| dnl
| #include <stdlib.h>
| #ifdef EXIT_SUCCESS
| yes
| #endif
| EOF
| if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
| egrep "yes" >/dev/null 2>&1; then
| rm -rf conftest*
| cat >> confdefs.h <<\EOF
| #define HAVE_EXIT_SUCCESS 1
| EOF
|
| the output is different, but still contains a dnl, in 2.50:
|
| # Check for ANSI C exit success/failure values.
| cat >conftest.$ac_ext <<_ACEOF
| #line 7556 "configure"
| #include "confdefs.h"
| dnl
| #include <stdlib.h>
| #ifdef EXIT_SUCCESS
| yes
| #endif
| _ACEOF
| if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
| egrep "yes" >/dev/null 2>&1; then
|
| cat >>confdefs.h <<\EOF
| #define HAVE_EXIT_SUCCESS 1
| EOF
So I'm very happy I added that test for `dnl' :) 2.50 just
denunciated a bug (in your input), which 2.13 kept hidden.
Wazaaaaaaaaaaa!
I should emphasize that this is a *bad* behavior of this macro, what
you wrote should give what you expect (well, not exactly because of
the closing quote masked by the hash): it corresponds to the `single
evaluation' rule. Here, as you can see, it's a zero evaluation, since
`dnl' is not expanded. In other words, this macro is double-quoting.
But we had to keep this for bugward compatibility :(
