Update to bsnes v018 release.

I began working on bsnes on October 14th, 2004. I am releasing bsnes v0.018 today to celebrate bsnes' two year anniversary. Please note that this release incurs a ~15% speed reduction since v0.017, due to IRQ and S-SMP timing improvements.
Changelog:
    - Fixed many critical errors in IRQ timing, should be *very* close to real hardware now
    - Corrected major CPU timing bug involving CPU I/O condition 4
    - Corrected bug with generic HiROM / LoROM memory maps
    - Corrected bug involving HDMA indirect channel termination [anomie]
    - OAM address reset now occurs when screen display is enabled, per recent research
    - Readded full DMA, HDMA and HDMA init bus sync timing
    - Added preliminary emulation of S-SMP $00f0 TEST register (6 of 8 bits are supported)
    - Readded emulation of known timing differences between CPU revisions 1 and 2
    - Config file can now control scanline-based PPU render position. This will only be needed until a proper dot-based PPU renderer is added
    - Removed core debugging hooks so that debugging console can remain in public releases, it now functions as a tracer and memory editor
    - Config file paths once again work correctly even if missing trailing backslash
    - Video configuration simplified, sorry in advance to those who enjoyed the profile mode used before
    - Added new configuration screen to control some emulation settings
    - Replaced bsnes program icon with a much nicer one [FitzRoy]
    - Optimized memory speed detection algorithm
    - Preliminary UPS soft-patching support (do not use this yet!)
    - Decreased memory usage and optimized generic libraries used by bsnes (/src/lib)
    - Now caching OAM by one line, somewhat similar to a real SNES. Fixes Winter Gold, but causes line rendering error in Mega lo Mania
    - Lots more, as usual
The following games have been fixed since v0.017 by the above bugfixes:
    - Battle Blaze (J, U)
    - Circuit USA (J)
    - F1 Grand Prix (J)
    - Funaki Masakatsu no Hybrid Wrestler - Tougi Denshou (J)
    - Jumbo Ozaki no Hole in One (J)
    - Mahjongg Taikai II (J)
    - RPG Tsukuru - Super Dante (J)
    - Robocop Versus The Terminator (U, E)
    - Sink or Swim (U, E)
    - Street Racer (J)
    - Touge Densetsu Saisoku Battle (J)
    - Winter Olympics (U, E)

src/chip/srtc/srtc.cpp

@@ -52,6 +52,8 @@
 
 #include "../../base.h"
 
+SRTC *srtc;
+
 void SRTC::set_time() {
 time_t rawtime;
 tm *t;