make MAX_CONFIGS a autoconf precious variable

You can now define up to how many configuration files you want
to support by stating something like

  ./configure MAX_CONFIGS=150 ...

when invoking configure. Default value remains 50.

configure.ac

@@ -39,6 +39,12 @@ AC_ARG_ENABLE(
 	[enable_distonly="no"]
 )
 
+AC_ARG_VAR([MAX_CONFIGS], [specify the maximum number of configs @<:@default=50@:>@])
+if test -z "$MAX_CONFIGS"; then
+	MAX_CONFIGS=50
+fi
+AC_DEFINE_UNQUOTED([MAX_CONFIGS], [$MAX_CONFIGS], [Maximum number of config files supported.])
+
 case "$host" in
 	*-mingw*)
 		CPPFLAGS="${CPPFLAGS} -DWIN32_LEAN_AND_MEAN"

options.h

@@ -37,7 +37,6 @@ typedef struct connection connection_t;
  * including the option name itself.
  */
 #define MAX_PARMS           5   /* May number of parameters per option */
-#define MAX_CONFIGS         50  /* Max number of config-files to read */
 #define MAX_CONFIG_SUBDIRS  50  /* Max number of subdirs to scan for configs */