Index: tools/build/v2/engine/build.jam
===================================================================
--- tools/build/v2/engine/build.jam	(revision 71186)
+++ tools/build/v2/engine/build.jam	(working copy)
@@ -17,12 +17,12 @@
 }
 
 # Platform related specifics.
-if $(NT) { rule .path { return "$(<:J=\\)" ; } ./ = "/" ; }
-else if $(OS2) { rule .path { return "$(<:J=\\)" ; } ./ = "/" ; }
-else if $(VMS) { rule .path { return "[.$(<:J=/)]" ; } }
-else if $(MAC) { rule .path { return ":$(<:J=\:)" ; } }
+if $(OS) = NT { rule .path { return "$(<:J=\\)" ; } ./ = "/" ; }
+else if $(OS) = OS2 { rule .path { return "$(<:J=\\)" ; } ./ = "/" ; }
+else if $(OS) = VMS { rule .path { return "[.$(<:J=/)]" ; } }
+else if $(OS) = MAC { rule .path { return ":$(<:J=\:)" ; } }
 else { rule .path { return "$(<:J=/)" ; } }
-if $(VMS) { . = "_" ; }
+if $(OS) = VMS { . = "_" ; }
 else { . = "." ; }
 ./ ?= "" ;
 
@@ -505,19 +505,19 @@
     modules/path.c modules/regex.c modules/property-set.c
     modules/sequence.c modules/order.c
     ;
-if $(NT)
+if $(OS) = NT
 {
     jam.source += execnt.c filent.c pathunix.c ;
 }
-else if $(OS2)
+else if $(OS) = OS2
 {
     jam.source += execunix.c fileos2.c pathunix.c ;
 }
-else if $(VMS)
+else if $(OS) = VMS
 {
     jam.source += execvms.c filevms.c pathvms.c ;
 }
-else if $(MAC)
+else if $(OS) = MAC
 {
     jam.source += execmac.c filemac.c pathmac.c ;
 }
@@ -565,7 +565,7 @@
 {
     --defs += NT ;
 }
-if $(VMS)
+if $(OS) = VMS
 {
     --defs += VMS ;
 }
@@ -591,22 +591,22 @@
 {
     [DELETE] clean : $(<) ;
 }
-if $(NT) { actions piecemeal together existing [DELETE] {
+if $(OS) = NT { actions piecemeal together existing [DELETE] {
     del /F /Q "$(>)"
 } }
-if $(UNIX) { actions piecemeal together existing [DELETE] {
+if $(UNIX) = true { actions piecemeal together existing [DELETE] {
     rm -f "$(>)"
 } }
-if $(VMS) { actions piecemeal together existing [DELETE] {
+if $(OS) = VMS { actions piecemeal together existing [DELETE] {
     DELETE $(>[--2]:J=";*, ") $(>[-1]);*
 } }
-if $(NT) {
+if $(OS) = NT {
     --chmod+w = "attrib -r " ;
 }
-if $(UNIX) {
+if $(UNIX) = true {
     --chmod+w = "chmod +w " ;
 }
-if $(VMS) {
+if $(OS) = VMS {
     --chmod+w = "SET FILE/PROT=(S:RWED) " ;
 }
 
@@ -616,13 +616,13 @@
     if $(<:P) { DEPENDS $(<) : $(<:P) ; .mkdir $(<:P) ; }
     if ! $(md<$(<)>) { [MKDIR] $(<) ; md<$(<)> = - ; }
 }
-if $(NT) { actions [MKDIR] {
+if $(OS) = NT { actions [MKDIR] {
     md "$(<)"
 } }
-if $(UNIX) { actions [MKDIR] {
+if $(UNIX) = true { actions [MKDIR] {
     mkdir "$(<)"
 } }
-if $(VMS) { actions [MKDIR] {
+if $(OS) = VMS { actions [MKDIR] {
     CREATE/DIR $(<J=", ")
 } }
 
@@ -684,13 +684,13 @@
     [LINK] $(<) : $(>) ;
     .clean $(<) ;
 }
-if $(NT) { actions [LINK] {
+if $(OS) = NT { actions [LINK] {
     copy "$(>)" "$(<)"
 } }
-if $(UNIX) { actions [LINK] {
+if $(UNIX) = true { actions [LINK] {
     ln -fs "$(>)" "$(<)"
 } }
-if $(VMS) { actions [LINK] {
+if $(OS) = VMS { actions [LINK] {
     COPY/REPLACE $(>) $(<)
 } }
 
@@ -713,14 +713,14 @@
     DEPENDS $(<) : $(>) ;
     [MOVE] $(<) : $(>) ;
 }
-if $(NT) { actions [MOVE] {
+if $(OS) = NT { actions [MOVE] {
     del /f "$(<)"
     rename "$(>)" "$(<)"
 } }
-if $(UNIX) { actions [MOVE] {
+if $(UNIX) = true { actions [MOVE] {
     mv -f "$(>)" "$(<)"
 } }
-if $(VMS) { actions [MOVE] {
+if $(OS) = VMS { actions [MOVE] {
     RENAME "$(>)" "$(<)"
 } }
 
@@ -749,7 +749,7 @@
 }
 
 # How to build the grammar.
-if $(NT)
+if $(OS) = NT
 {
     SUFEXE = .exe ;
     # try some other likely spellings...
@@ -779,7 +779,7 @@
     LEAVES $(<) ;
     [YACC] $(<) : $(>) ;
 }
-if $(NT) { actions [YACC] {
+if $(OS) = NT { actions [YACC] {
     "$(yacc)" "$(>)"
     if not errorlevel 1 (
         del /f "$(<[1])"
@@ -788,7 +788,7 @@
         rename y.tab$(<[2]:S) "$(<[2])"
     ) else set _error_ =
 } }
-if $(UNIX) { actions [YACC] {
+if $(UNIX) = true { actions [YACC] {
     if ` "$(yacc)" "$(>)" ` ; then
         mv -f y.tab$(<[1]:S) "$(<[1])"
         mv -f y.tab$(<[2]:S) "$(<[2])"
@@ -796,7 +796,7 @@
         exit 1
     fi
 } }
-if $(VMS) { actions [YACC] {
+if $(OS) = VMS { actions [YACC] {
     IF "$(yacc)" $(>)
     THEN
         RENAME y_tab$(<[1]:S) $(<[1])
@@ -913,7 +913,7 @@
     $(dist.bin:S=$(bjam.exe:S))
     ;
 
-if $(NT)
+if $(OS) = NT
 {
     zip ?= [ GLOB "$(ProgramFiles:J= )\\7-ZIP" "C:\\Program Files\\7-ZIP" : "7z.exe" ] ;
     zip ?= [ GLOB "$(ProgramFiles:J= )\\7-ZIP" "C:\\Program Files\\7-ZIP" : "7zn.exe" ] ;
@@ -935,7 +935,7 @@
     copy /Y "$(>)" "$(<)" >NUL:
     }
 }
-if $(UNIX)
+if $(UNIX) = true
 {
     tar ?= [ GLOB $(PATH) : star bsdtar tar ] ;
     tar = $(tar[1]) ;
@@ -962,14 +962,14 @@
 rule .binary
 {
     local zip = ;
-    if $(NT) { zip = $($(<).exe:S=.zip) ; }
-    if $(UNIX) { zip = $($(<).exe:S=.tgz) ; }
+    if $(OS) = NT { zip = $($(<).exe:S=.zip) ; }
+    if $(UNIX) = true { zip = $($(<).exe:S=.tgz) ; }
     zip = $(zip:S=)-$(VERSION)-$(RELEASE)-$(platform)$(zip:S) ;
     DEPENDS $(zip) : $($(<).exe) ;
     DEPENDS dist : $(zip) ;
     #~ LOCATE on $(zip) = $(locate-target) ;
-    if $(NT) { [ZIP] $(zip) : $($(<).exe) ; }
-    if $(UNIX) { [PACK] $(zip) : $($(<).exe) ; }
+    if $(OS) = NT { [ZIP] $(zip) : $($(<).exe) ; }
+    if $(UNIX) = true { [PACK] $(zip) : $($(<).exe) ; }
     .clean $(zip) ;
 }
 
@@ -995,8 +995,8 @@
     }
 
     local pack = ;
-    if $(NT) { pack = $(dst-dir).zip ; }
-    if $(UNIX) { pack = $(dst-dir).tgz ; }
+    if $(OS) = NT { pack = $(dst-dir).zip ; }
+    if $(UNIX) = true { pack = $(dst-dir).tgz ; }
 
     DEPENDS dist : $(pack) ;
     DEPENDS $(pack) : $(dst-files) ;