[PATCH] configure: Properly handle MM_DEBUG

[Glenn Washburn]

Define MM_DEBUG in config.h when --enable-mm-debug is passed to configure.
It was being defined in config-util.h which only gets used when building
GRUB utilities for the host side. The enabling of debugging for memory
management in include/grub/mm.h explicitly does not happen when compiling
for the GRUB utilities. So this debugging code effectively could never be
enabled. Note, that MM_DEBUG is defined in an #if directive because the
enabling of debugging checks if MM_DEBUG is defined, not what its value is.
So even if MM_DEBUG were defined to nothing, the debugging code would
still be enabled.

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
I just got bit by this, and then remembered that Daniel A had something similar,
which inadvertently always enables MM_DEBUG. I believe this patch addresses
the concern that Daniel K had with that patch. Technically, the #undef is
unnecessary and I'm not opposed to taking it out.

Glenn

---
 config.h.in  | 6 ++++++
 configure.ac | 6 ++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/config.h.in b/config.h.in
index 9e8f9911b..9063e8149 100644
--- a/config.h.in
+++ b/config.h.in
@@ -9,6 +9,12 @@
 #define GCRYPT_NO_DEPRECATED 1
 #define HAVE_MEMMOVE 1
 
+#if @MM_DEBUG@
+#define MM_DEBUG @MM_DEBUG@
+#else
+#undef MM_DEBUG
+#endif
+
 /* Define to 1 to enable disk cache statistics.  */
 #define DISK_CACHE_STATS @DISK_CACHE_STATS@
 #define BOOT_TIME_STATS @BOOT_TIME_STATS@
diff --git a/configure.ac b/configure.ac
index 4f649edaf..263f02775 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1511,9 +1511,11 @@ AC_ARG_ENABLE([mm-debug],
              AS_HELP_STRING([--enable-mm-debug],
                              [include memory manager debugging]))
 if test x$enable_mm_debug = xyes; then
-    AC_DEFINE([MM_DEBUG], [1],
-            [Define to 1 if you enable memory manager debugging.])
+    MM_DEBUG=1
+else
+    MM_DEBUG=0
 fi
+AC_SUBST([MM_DEBUG])
 
 AC_ARG_ENABLE([cache-stats],
              AS_HELP_STRING([--enable-cache-stats],
-- 
2.27.0