Variety of performance improvements.

* bjam; bump to version 3.1.12
* bjam; make it possible to build in MinGW/MSYS shell
* bjam; move profile code to debug.h/c to make it available for use everywhere
* bjam; cache all filesystem query operations, Unix and Windows only, include PWD and scanning
* bjam; add memory profile info, and sprinkle throught code
* bbv2; rewrite some while() loops into for() loops to reduce time and memory
* bbv2; keep a single instance counter instead of one per type to reduce memory use
* bjam+bbv2; change NORMALIZE_PATH builtin to join path parts to reduce memory use


[SVN r31177]

src/engine/debug.h

@@ -0,0 +1,53 @@
+/*
+    Copyright Rene Rivera 2005.
+    Distributed under the Boost Software License, Version 1.0.
+    (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BJAM_DEBUG_H
+#define BJAM_DEBUG_H
+
+# include "jam.h"
+# include <time.h>
+
+struct profile_info
+{
+    /* name of rule being called */
+    char* name;
+    /* cumulative time spent in rule */
+    clock_t cumulative;
+    /* time spent in rule proper */
+    clock_t net;
+    /* number of time rule was entered */
+    unsigned long num_entries;
+    /* number of the times this function is present in stack */
+    unsigned long stack_count;
+    /* bytes of memory allocated by the call */
+    unsigned long memory;
+};
+typedef struct profile_info profile_info;
+
+struct profile_frame
+{
+    /* permanent storage where data accumulates */
+    profile_info* info;
+    /* overhead for profiling in this call */
+    clock_t overhead;
+    /* time of last entry to rule */
+    clock_t entry_time;
+    /* stack frame of caller */
+    struct profile_frame* caller;
+    /* time spent in subrules */
+    clock_t subrules;
+};
+typedef struct profile_frame profile_frame;
+
+profile_frame * profile_init( char* rulename, profile_frame* frame );
+void profile_enter( char* rulename, profile_frame* frame );
+void profile_memory( long mem );
+void profile_exit(profile_frame* frame);
+void profile_dump();
+
+#define PROFILE_ENTER(scope) profile_frame PROF_ ## scope, *PROF_ ## scope ## _p = profile_init(#scope,&PROF_ ## scope)
+#define PROFILE_EXIT(scope) profile_exit(PROF_ ## scope ## _p)
+
+#endif