osc7: initial patch implementation (#154)

* osc7: initial patch implementation

Closes #153

* osc7: avoid redundant use of realpath()

* osc7: fix styling

* Changing position of the OSC7_PATCH toggle in patches.def.h

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Co-authored-by: Bakkeby <bakkeby@gmail.com>

st.h

@@ -205,6 +205,9 @@ typedef struct {
 	ImageList *images_alt; /* sixel images for alternate screen */
 	#endif // SIXEL_PATCH
 	Rune lastc;   /* last printed char outside of sequence, 0 if control */
+	#if OSC7_PATCH
+	char* cwd;    /* current working directory */
+	#endif // OSC7_PATCH
 } Term;
 
 typedef union {