--- a/tools/build/src/tools/darwin.jam	2018-08-01 15:50:55.000000000 -0500
+++ b/tools/build/src/tools/darwin.jam	2019-03-10 00:29:34.859932848 -0600
@@ -199,7 +199,7 @@
     }
     
     # - Initialize the SDKs available in the root for this tool.
-    local sdks = [ init-available-sdk-versions $(condition) : $(root) ] ;
+#    local sdks = [ init-available-sdk-versions $(condition) : $(root) ] ;
     
     #~ ECHO --- ;
     #~ ECHO --- bin :: $(bin) ;
@@ -213,200 +213,6 @@
     #~ EXIT ;
 }
 
-# Add and set options for a discovered SDK version.
-local rule init-sdk ( condition * : root ? : version + : version-feature ? )
-{
-    local rule version-to-feature ( version + )
-    {
-        switch $(version[1])
-        {
-            case appletv* :
-            {
-                return $(version[1])-$(version[2-]:J=.) ;
-            }
-            case iphone* :
-            {
-                return $(version[1])-$(version[2-]:J=.) ;
-            }
-            case mac* :
-            {
-                return $(version[2-]:J=.) ;
-            }
-            case * :
-            {
-                return $(version:J=.) ;
-            }
-        }
-    }
-    
-    if $(version-feature)
-    {
-        if $(.debug-configuration)
-        {
-            ECHO notice\: available sdk for $(condition)/<macosx-version>$(version-feature) at $(root) ;
-        }
-        
-        # Add the version to the features for specifying them.
-        if ! $(version-feature) in [ feature.values macosx-version ]
-        {
-            feature.extend macosx-version : $(version-feature) ;
-        }
-        if ! $(version-feature) in [ feature.values macosx-version-min ]
-        {
-            feature.extend macosx-version-min : $(version-feature) ;
-        }
-        
-        # Set the flags the version needs to compile with, first
-        # generic options.
-        flags darwin.compile OPTIONS $(condition)/<macosx-version>$(version-feature)
-            : -isysroot $(root) ;
-        flags darwin.link OPTIONS $(condition)/<macosx-version>$(version-feature)
-            : -isysroot $(root) ;
-        
-        # Then device variation options.
-        switch $(version[1])
-        {
-            case appletvsim* :
-            {
-                local N = $(version[2]) ;
-                if ! $(version[3]) { N += 00 ; }
-                else if [ regex.match (..) : $(version[3]) ] { N += $(version[3]) ; }
-                else { N += 0$(version[3]) ; }
-                if ! $(version[4]) { N += 00 ; }
-                else if [ regex.match (..) : $(version[4]) ] { N += $(version[4]) ; }
-                else { N += 0$(version[4]) ; }
-                N = $(N:J=) ;
-                flags darwin.compile OPTIONS <macosx-version-min>$(version-feature)
-                    : -D__IPHONE_OS_VERSION_MIN_REQUIRED=$(N) ;
-                flags darwin.link OPTIONS <macosx-version-min>$(version-feature)
-                    : -D__IPHONE_OS_VERSION_MIN_REQUIRED=$(N) ;
-            }
-
-            case appletv* :
-            {
-                flags darwin.compile OPTIONS <macosx-version-min>$(version-feature)
-                    : -mtvos-version-min=$(version[2-]:J=.) ;
-                flags darwin.link OPTIONS <macosx-version-min>$(version-feature)
-                    : -mtvos-version-min=$(version[2-]:J=.) ;
-            }
-
-            case iphonesim* :
-            {
-                local N = $(version[2]) ;
-                if ! $(version[3]) { N += 00 ; }
-                else if [ regex.match (..) : $(version[3]) ] { N += $(version[3]) ; }
-                else { N += 0$(version[3]) ; }
-                if ! $(version[4]) { N += 00 ; }
-                else if [ regex.match (..) : $(version[4]) ] { N += $(version[4]) ; }
-                else { N += 0$(version[4]) ; }
-                N = $(N:J=) ;
-                flags darwin.compile OPTIONS <macosx-version-min>$(version-feature)
-                    : -D__IPHONE_OS_VERSION_MIN_REQUIRED=$(N) ;
-                flags darwin.link OPTIONS <macosx-version-min>$(version-feature)
-                    : -D__IPHONE_OS_VERSION_MIN_REQUIRED=$(N) ;
-            }
-
-            case iphone* :
-            {
-                flags darwin.compile OPTIONS <macosx-version-min>$(version-feature)
-                    : -miphoneos-version-min=$(version[2-]:J=.) ;
-                flags darwin.link OPTIONS <macosx-version-min>$(version-feature)
-                    : -miphoneos-version-min=$(version[2-]:J=.) ;
-            }
-            
-            case mac* :
-            {
-                flags darwin.compile OPTIONS <macosx-version-min>$(version-feature)
-                    : -mmacosx-version-min=$(version[2-]:J=.) ;
-                flags darwin.link OPTIONS <macosx-version-min>$(version-feature)
-                    : -mmacosx-version-min=$(version[2-]:J=.) ;
-            }
-        }
-        
-        if $(version[3]) > 0
-        {
-            # We have a minor version of an SDK. We want to set up
-            # previous minor versions, plus the current minor version.
-            # So we recurse to set up the previous minor versions, up to
-            # the current version.
-            local minor-minus-1 = [ CALC $(version[3]) - 1 ] ;
-            return
-                [ init-sdk $(condition) : $(root)
-                    : $(version[1-2]) $(minor-minus-1) : [ version-to-feature $(version[1-2]) $(minor-minus-1) ] ]
-                $(version-feature) ;
-        }
-        else
-        {
-            return $(version-feature) ;
-        }
-    }
-    else if $(version[4])
-    {
-        # We have a patch version of an SDK. We want to set up
-        # both the specific patch version, and the minor version.
-        # So we recurse to set up the patch version. Plus the minor version.
-        return
-            [ init-sdk $(condition) : $(root)
-                : $(version[1-3]) : [ version-to-feature $(version[1-3]) ] ]
-            [ init-sdk $(condition) : $(root)
-                : $(version) : [ version-to-feature $(version) ] ] ;
-    }
-    else
-    {
-        # Yes, this is intentionally recursive.
-        return
-            [ init-sdk $(condition) : $(root)
-                : $(version) : [ version-to-feature $(version) ] ] ;
-    }
-}
-
-# Determine the MacOSX SDK versions installed and their locations.
-local rule init-available-sdk-versions ( condition * : root ? )
-{
-    root ?= /Developer ;
-    local sdks-root = $(root)/SDKs ;
-    local sdks = [ GLOB $(sdks-root) : MacOSX*.sdk AppleTVOS*.sdk AppleTVSimulator*.sdk iPhoneOS*.sdk iPhoneSimulator*.sdk ] ;
-    local result ;
-    for local sdk in $(sdks)
-    {
-        local sdk-match = [ MATCH "([^0-9]+)([0-9]+)[.]([0-9x]+)[.]?([0-9x]+)?" : $(sdk:D=) ] ;
-        local sdk-platform = $(sdk-match[1]:L) ;
-        local sdk-version = $(sdk-match[2-]) ;
-        if $(sdk-version)
-        {
-            switch $(sdk-platform)
-            {
-                case macosx :
-                {
-                    sdk-version = mac $(sdk-version) ;
-                }
-                case appletvos :
-                {
-                    sdk-version = appletv $(sdk-version) ;
-                }
-                case appletvsimulator :
-                {
-                    sdk-version = appletvsim $(sdk-version) ;
-                }
-                case iphoneos :
-                {
-                    sdk-version = iphone $(sdk-version) ;
-                }
-                case iphonesimulator :
-                {
-                    sdk-version = iphonesim $(sdk-version) ;
-                }
-                case * :
-                {
-                    sdk-version = $(sdk-version:J=-) ;
-                }
-            }
-            result += [ init-sdk $(condition) : $(sdk) : $(sdk-version) ] ;
-        }
-    }
-    return $(result) ;
-}
-
 # Generic options.
 flags darwin.compile OPTIONS <flags> ;
 
@@ -497,14 +303,14 @@
             }
         }
         
-        case arm :
-        {
-            if $(instruction-set) {
-                options = -arch$(_)$(instruction-set) ;
-            } else {
-                options = -arch arm ;
-            }
-        }
+#        case arm :
+#        {
+#            if $(instruction-set) {
+#                options = -arch$(_)$(instruction-set) ;
+#            } else {
+#                options = -arch arm ;
+#            }
+#        }
     }
     
     if $(options)