Make it more like the one that is generated by autotools.
It is true that Visual C++ has sig_atomic_t, at least for Visual C++ 2008
and later, but this is currently only used for UNIX builds of GLib, as a
point of note here.
/* Define to 1 if you have the <pwd.h> header file. */
/* #undef HAVE_PWD_H */
-/* Define to 1 if you have the 'qsort_r' function */
-/* #undef HAVE_QSORT_R */
-
/* Define to 1 if you have the `readlink' function. */
/* #undef HAVE_READLINK */
/* Define to 1 if you have the `setmntent' function. */
/* #undef HAVE_SETMNTENT */
+/* Define if you have the 'sig_atomic_t' type. */
+#define HAVE_SIG_ATOMIC_T 1
+
/* Define to 1 if you have the `snprintf' function. */
#ifndef _MSC_VER
#define HAVE_SNPRINTF 1