[ #4786 ] if space in the Application path name, system() doesn't work on some platforms

commited temporary fix: executable name is quoted for all platforms except Windows now,
nicely wrapped in #ifdefs. Will be doing nice wrapper function BLI_system for system calls in blenlib
after release.
Please test on all platforms!

source/blender/python/api2_2x/sceneRender.c

@@ -508,8 +508,13 @@ PyObject *RenderData_Play( BPy_RenderData * self )
 		BKE_makepicstring( file, G.scene->r.pic, self->renderContext->sfra, G.scene->r.imtype);
 		if( BLI_exist( file ) ) {
 			calc_renderwin_rectangle(640, 480, G.winpos, pos, size);
+#ifdef WIN32
 			sprintf( str, "%s -a -p %d %d \"%s\"", bprogname,
 				 pos[0], pos[1], file );
+#else
+			sprintf( str, "\"%s\" -a -p %d %d \"%s\"", bprogname,
+				 pos[0], pos[1], file );
+#endif
 			system( str );
 		} else
 			sprintf( "Can't find image: %s", file );

source/blender/src/buttons_scene.c

@@ -505,8 +505,11 @@ static void run_playanim(char *file)
 	/* use current settings for defining position of window. it actually should test image size */
 	calc_renderwin_rectangle((G.scene->r.xsch*G.scene->r.size)/100, 
 							 (G.scene->r.ysch*G.scene->r.size)/100, G.winpos, pos, size);
-
+#ifdef WIN32
 	sprintf(str, "%s -a -p %d %d \"%s\"", bprogname, pos[0], pos[1], file);
+#else
+	sprintf(str, "\"%s\" -a -p %d %d \"%s\"", bprogname, pos[0], pos[1], file);
+#endif
 	system(str);
 }
 

source/blender/src/editimasel.c

@@ -340,8 +340,11 @@ void winqreadimaselspace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 	case PKEY:
 		if(G.qual & LR_SHIFTKEY) {
 			extern char bprogname[];	/* usiblender.c */
-			
+#ifdef WIN32			
 			sprintf(name, "%s -a \"%s%s\"", bprogname, simasel->dir, simasel->file);
+#else
+			sprintf(name, "\"%s\" -a \"%s%s\"", bprogname, simasel->dir, simasel->file);
+#endif
 			system(name);
 		}
 		if(G.qual & LR_CTRLKEY) {

source/blender/src/filesel.c

@@ -2222,8 +2222,11 @@ void winqreadfilespace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 		case PKEY:
 			if(G.qual & LR_SHIFTKEY) {
 				extern char bprogname[];	/* usiblender.c */
-			
+#ifdef WIN32			
 				sprintf(str, "%s -a \"%s%s\"", bprogname, sfile->dir, sfile->file);
+#else
+				sprintf(str, "\"%s\" -a \"%s%s\"", bprogname, sfile->dir, sfile->file);
+#endif
 				system(str);
 			}
 			else