CHANGE: evaluating user.reb file if found in user's home directory.

Home directory (`system/options/home`) can be set by using one of `REBOL_HOME`, `USERPROFILE` or `HOME` environmental variables (preference in this order). If none of these is defined, as home is used same directory as directory with used executable.

Related: Oldes/Rebol-issues#706
Related: Oldes/Rebol-issues#707
Related: Oldes/Rebol-issues#1207
Related: Oldes/Rebol-issues#1208

src/mezz/mezz-tail.reb

@@ -31,6 +31,3 @@ system/options/boot: clean-path system/options/boot
 
 ;protect system/standard
 protect-system-object
-
-;- try to execute file with user preferences
-if exists? ~/user.r3 [ try [do ~/user.r3] ]

src/mezz/sys-start.reb

@@ -51,7 +51,7 @@ start: func [
 		get-env "REBOL_HOME"  ; User can set this environment variable with own location
 		get-env "USERPROFILE" ; Default user's home directory on Windows
 		get-env "HOME"        ; Default user's home directory on Linux
-		home
+		file                  ; Directory where is the executable
 	]
 	if file? script [ ; Get the path (needed for SECURE setup)
 		script-path: split-path script
@@ -121,7 +121,14 @@ start: func [
 		flags/secure [secure]
 		flags/secure-min ['allow]
 		flags/secure-max ['quit]
-		file? script [compose [file throw (file) [allow read] (first script-path) allow]]
+		file? script [
+			compose [
+				file throw
+				(file) [allow read]
+				(home) [allow read]
+				(first script-path) allow
+			]
+		]
 		'else ['none] ;compose [file throw (file) [allow read] %. allow]] ; default
 	])
 
@@ -134,8 +141,8 @@ start: func [
 	append tmp reduce ['system :system 'local-lib :tmp]
 	system/contexts/user: tmp
 
-	;boot-print ["Checking for user.reb file in" file]
-	;if exists? file/user.reb [do file/user.reb]
+	boot-print ["Checking for user.reb file in" home]
+	if exists? home/user.reb [do home/user.reb]
 
 	boot-print ""