fix autogen.sh for WSL/Windows file link attempt

autogen.sh

@@ -5,12 +5,39 @@
 
 set -e
 
+# Check environment
+if [ -n "$WSL_DISTRO_NAME" ]; then
+    # we found a non-blank WSL environment distro name
+    current_path="$(pwd)"
+    pattern="/mnt/?"
+    if [ "$(echo "$current_path" | grep -E "^$pattern")" ]; then
+        # if we are in WSL and shared Windows file system, 'ln' does not work.
+        no_links=true
+    else
+        no_links=
+    fi
+fi
+
 # Git hooks should come before autoreconf.
 if test -d .git; then
-  if ! test -d .git/hooks; then
-    mkdir .git/hooks
-  fi
-  ln -s -f ../../pre-commit.sh .git/hooks/pre-commit
+    if [ -n "$no_links" ]; then
+        echo "Linux ln does not work on shared Windows file system in WSL."
+        if [ ! -e .git/hooks/pre-commit ]; then
+            echo "The pre-commit.sh file will not be copied to .git/hooks/pre-commit"
+            # shell scripts do not work on Windows; TODO create equivalent batch file
+            # cp ./pre-commit.sh .git/hooks/pre-commit || exit $?
+        fi
+        if [ ! -e .git/hooks/pre-push ]; then
+            echo "The pre-push.sh file will not be copied to .git/hooks/pre-commit"
+            # shell scripts do not work on Windows; TODO create equivalent batch file
+            # cp ./pre-push.sh .git/hooks/pre-push || exit $?
+        fi
+    else
+      if ! test -d .git/hooks; then
+        mkdir .git/hooks
+      fi
+      ln -s -f ../../pre-commit.sh .git/hooks/pre-commit
+    fi
 fi
 
 # if get an error about libtool not setup