make.tcl only search for sdx after determining if there are runtimes to install

src/make.tcl

@@ -42,11 +42,6 @@ if {![llength $vfs_folders]} {
 }
 file mkdir $sourcefolder/_build
 
-if {[catch {exec sdx help} errM]} {
-    puts stderr "FAILED to find usable sdx command - check that sdx executable is on path"
-    puts stderr "err: $errM"
-    exit 1
-}
 #find runtime - only supports one for now.. REVIEW
 set rtfolder $sourcefolder/runtime
 set runtimes [glob -nocomplain -dir $rtfolder -types {f x} -tail *]
@@ -54,6 +49,14 @@ if {![llength $runtimes]} {
     puts stderr "No executable runtimes found in $rtfolder - unable to build any .vfs folders into executables."
     exit 2
 }
+
+if {[catch {exec sdx help} errM]} {
+    puts stderr "FAILED to find usable sdx command - check that sdx executable is on path"
+    puts stderr "err: $errM"
+    exit 1
+}
+
+
 if {[llength $runtimes] > 1} {
     puts stderr "Found multiple runtimes in $rtfolder ($runtimes)  - unable to proceed - currently limited to one."
     exit 3