examples: Suffix package exe with .exe on Windows

Without this the vscode extension cannot find the example executable, and the example fails.

Also use $USERPROFILE instead of  $HOME for finding the `.vscode` user directory for installing the extension.

Bug: #12
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ac15424..79ff71f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -85,10 +85,13 @@
 ###########################################################
 if(CMAKE_SYSTEM_NAME MATCHES "Windows")
     set(CPPDAP_OS_LIBS WS2_32)
+    set(CPPDAP_OS_EXE_EXT ".exe")
 elseif(CMAKE_SYSTEM_NAME MATCHES "Linux")
     set(CPPDAP_OS_LIBS pthread)
+    set(CPPDAP_OS_EXE_EXT "")
 elseif(CMAKE_SYSTEM_NAME MATCHES "Darwin")
     set(CPPDAP_OS_LIBS)
+    set(CPPDAP_OS_EXE_EXT "")
 endif()
 
 ###########################################################
@@ -230,7 +233,11 @@
         target_link_libraries(${target} cppdap "${CPPDAP_OS_LIBS}")
 
         if(CPPDAP_INSTALL_VSCODE_EXAMPLES)
-            set(extroot "$ENV{HOME}/.vscode/extensions")
+            if(CMAKE_SYSTEM_NAME MATCHES "Windows")
+                set(extroot "$ENV{USERPROFILE}\\.vscode\\extensions")
+            else()
+                set(extroot "$ENV{HOME}/.vscode/extensions")
+            endif()
             if(EXISTS ${extroot})
                 set(extdir "${extroot}/google.cppdap-example-${target}-1.0.0")
                 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/examples/vscode/package.json ${extdir}/package.json)
diff --git a/examples/vscode/package.json b/examples/vscode/package.json
index bd9e378..9a52413 100644
--- a/examples/vscode/package.json
+++ b/examples/vscode/package.json
@@ -19,7 +19,7 @@
         "debuggers": [
             {
                 "type": "@target@",
-                "program": "@target@",
+                "program": "@target@@CPPDAP_OS_EXE_EXT@",
                 "label": "cppdap example: @target@",
                 "configurationAttributes": {}
             }