replace PATCH_STITCHING preprocessor define with r_patchStitching cvar #189

Job	Run time
WinXP x86 Release (Non-Portable)	9m 35s
Ubuntu x86 Debug (Non-Portable)	3m 29s
macOS x86_64 Debug (Non-Portable)	3m 3s
WinXP x86_64 Release (Non-Portable)	9m 6s
Ubuntu x86 Release (Non-Portable)	4m 23s
Windows x86 Debug (Non-Portable)	3m 52s
macOS x86_64 Release (Non-Portable)	8m 30s
Ubuntu x86_64 Debug (Non-Portable)	2m 33s
Windows x86 Release (Portable)	3m 59s
Ubuntu x86_64 Release (Non-Portable)	4m 0s
Windows x86 Release (Non-Portable)	4m 23s
Windows x86_64 Debug (Non-Portable)	3m 38s
Windows x86_64 Release (Portable)	4m 36s
Windows x86_64 Release (Non-Portable)	4m 40s
create-release	0s
create-latest	0s
	1h 9m 47s

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