Fix compilation on Gentoo/FreeBSD, no alloca.h here and PATH_MAX
is defined elsewhere.

See bug 254795

--- logrotate-3.7.7.orig/config.c
+++ logrotate-3.7.7/config.c
@@ -21,6 +21,9 @@
 #include <wctype.h>
 #include <fnmatch.h>
 
+#if !defined(PATH_MAX) && defined(__FreeBSD__)
+#include <sys/param.h>
+#endif
 #include "basenames.h"
 #include "log.h"
 #include "logrotate.h"
--- logrotate-3.7.7.orig/logrotate.c
+++ logrotate-3.7.7/logrotate.c
@@ -24,6 +24,9 @@
 int selinux_enforce = 0;
 #endif
 
+#if !defined(PATH_MAX) && defined(__FreeBSD__)
+#include <sys/param.h>
+#endif
 #include "basenames.h"
 #include "log.h"
 #include "logrotate.h"