msvs build: only fix_file_list when it is broken

Clears a warning when generating VS project files with older versions of
bash:
declare: -n: invalid option

Change-Id: Id0c0bc17dc5a1599f7d2d73e3cc9259a45540f3f

build/make/msvs_common.sh

@@ -41,6 +41,15 @@ fix_path() {
 # Corrects the paths in file_list in one pass for efficiency.
 # $1 is the name of the array to be modified.
 fix_file_list() {
+    if [ "${FIXPATH}" = "echo_path" ] ; then
+      # When used with echo_path, fix_file_list is a no-op. Avoid warning about
+      # unsupported 'declare -n' when it is not important.
+      return 0
+    elif [ "${BASH_VERSINFO}" -lt 4 ] ; then
+      echo "Cygwin path conversion has failed. Please use a version of bash"
+      echo "which supports nameref (-n), introduced in bash 4.3"
+      return 1
+    fi
     declare -n array_ref=$1
     files=$(fix_path "${array_ref[@]}")
     local IFS=$'\n'