begin splitting up source files, so we can have a tree of sources...

unique to each architecture.  For now, we have "esp32" and "bare"

esp32 is the old esp stuff

bare is an target suitable for emulation that doesn't require any
particular hardware to run (no bluetooth, no i2c devices, no spi devices)

platformio.ini

@@ -15,6 +15,11 @@ default_envs = tbeam
 ; default to a US frequency range, change it as needed for your region and hardware (CN, JP, EU433, EU865)
 hw_version = US
 
+; Common settings for ESP targes, mixin with extends = esp32_base
+[esp32_base]
+src_filter = 
+  ${env.src_filter} -<bare/>
+
 [env]
 platform = espressif32
 framework = arduino
@@ -70,7 +75,8 @@ lib_deps =
   https://github.com/meshtastic/SparkFun_Ublox_Arduino_Library.git
 
 ; The 1.0 release of the TBEAM board
-[env:tbeam] 
+[env:tbeam]
+extends = esp32_base
 board = ttgo-t-beam
 lib_deps =
   ${env.lib_deps}
@@ -79,22 +85,26 @@ build_flags =
   ${env.build_flags} -D TBEAM_V10
 
 ; The original TBEAM board without the AXP power chip and a few other changes
-[env:tbeam0.7] 
+[env:tbeam0.7]
+extends = esp32_base
 board = ttgo-t-beam
 build_flags = 
   ${env.build_flags} -D TBEAM_V07
 
 [env:heltec]
 ;build_type = debug ; to make it possible to step through our jtag debugger 
+extends = esp32_base
 board = heltec_wifi_lora_32_V2
 
 [env:ttgo-lora32-v1]
+extends = esp32_base
 board = ttgo-lora32-v1
 build_flags = 
   ${env.build_flags} -D TTGO_LORA_V1
 
 ; note: the platformio definition for lora32-v2 seems stale, it is missing a pins_arduino.h file, therefore I don't think it works
 [env:ttgo-lora32-v2]
+extends = esp32_base
 board = ttgo-lora32-v1
 build_flags = 
   ${env.build_flags} -D TTGO_LORA_V2
@@ -104,4 +114,8 @@ build_flags =
 [env:bare]
 board = ttgo-lora32-v1
 build_flags = 
-  ${env.build_flags} -D BARE_BOARD
+  ${env.build_flags} -D BARE_BOARD
+src_filter = 
+  ${env.src_filter} -<esp32/>
+lib_ignore =
+  BluetoothOTA