refactor Build Date, GIT_TAG, and GIT_HASH support

platformio.ini

@@ -25,6 +25,11 @@ build_flags =
     ; -isystem /home/tom/.platformio/packages/framework-espidf/components/esp_libc/platform_include
     -Wno-include-next
 ; --- STRICT MODE FOR PROJECT APPLICATION CODE ONLY ---
+
+    #-DGIT_HASH=\"\"${sysenv.GIT_HASH}\"\"
+    !echo -DGIT_HASH=\\\"$(git rev-parse --short HEAD)\\\"
+    !echo -DGIT_TAG=\\\"$(git describe --tags --always)\\\"
+
 ; These flags are strictly applied ONLY to C++ files inside the src/ directory.
 build_src_flags =
     ; Enables all standard compiler warning flags