Change mmap I/O default mode to enable

Author: wkliao

darshan-runtime/configure.ac

@@ -119,9 +119,9 @@ if test "x$enable_darshan_runtime" = xyes ; then
    fi
 
    AC_ARG_ENABLE([mmap-logs],
-      [AS_HELP_STRING([--enable-mmap-logs],
-                      [Enables ability to mmap I/O data to log file])],
-      [], [enable_mmap_logs=no]
+      [AS_HELP_STRING([--disable-mmap-logs],
+                      [Disables ability to mmap I/O data to log file])],
+      [], [enable_mmap_logs=yes]
    )
    if test "x$enable_mmap_logs" = "xyes" ; then
       AC_DEFINE([__DARSHAN_ENABLE_MMAP_LOGS], 1,

darshan-runtime/doc/darshan-runtime.rst

@@ -142,7 +142,7 @@ Compilation
   header and library.
 * ``--without-mpi``: disables MPI support when building Darshan - MPI support is
   assumed if not specified.
-* ``--enable-mmap-logs``: enables the use of Darshan's mmap log file mechanism.
+* ``--disable-mmap-logs``: disables the use of Darshan's mmap log file mechanism.
 * ``--enable-cuserid``: enables use of cuserid() at runtime.
 * ``--disable-ld-preload``: disables building of the Darshan ``LD_PRELOAD`` library
 * ``--enable-group-readable-logs``: sets Darshan log file permissions to allow