FLASH_DISCRIM causing every target to always full rebuild

src/.gitignore

@@ -8,4 +8,5 @@ python/__pycache__/
 *.pyc
 super_defines.txt
 include/WebContent.h
+include/flashdiscrim.h
 .DS_Store

src/lib/OPTIONS/options.cpp

@@ -166,9 +166,9 @@ firmware_options_t firmwareOptions;
 bool options_init()
 {
     firmwareOptions = flashedOptions;
-#if defined(TARGET_STM32) && defined(FLASH_DISCRIM)
-    // This is defined by the build_flags.py and used by STM32 (ESP gets it from json)
-    // It is always defined even though intellisense doesn't pick it up
+#if defined(PLATFORM_STM32)
+    #include "flashdiscrim.h"
+    // This is created by the build_flags.py and used by STM32 (ESP gets it from json)
     flash_discriminator = FLASH_DISCRIM;
 #endif
     return true;

src/python/build_flags.py

@@ -136,18 +136,17 @@ def get_git_sha():
 def get_version():
     return string_to_ascii(env.get('GIT_VERSION'))
 
-json_flags['flash-discriminator'] = randint(1,2**32-1)
-json_flags['wifi-on-interval'] = -1
-
 process_flags("user_defines.txt")
 process_flags("super_defines.txt") # allow secret super_defines to override user_defines
 version_to_env()
 build_flags.append("-DLATEST_COMMIT=" + get_git_sha())
 build_flags.append("-DLATEST_VERSION=" + get_version())
 build_flags.append("-DTARGET_NAME=" + re.sub("_VIA_.*", "", target_name))
-build_flags.append("-DFLASH_DISCRIM=" + str(json_flags['flash-discriminator']))
 condense_flags()
 
+json_flags['flash-discriminator'] = randint(1,2**32-1)
+json_flags['wifi-on-interval'] = -1
+
 if '-DRADIO_SX127X=1' in build_flags:
     # disallow setting 2400s for 900
     if fnmatch.filter(build_flags, '*-DRegulatory_Domain_ISM_2400') or \
@@ -205,3 +204,7 @@ def get_version():
 stm = env.get('PIOPLATFORM', '') in ['ststm32']
 if stm:
     env['UPLOAD_PROTOCOL'] = 'custom'
+    # -DFLASH_DISCRIM=xxxx can't be passed on the command line or it will every file to
+    # always be rebuilt, so put it in a header that options.cpp can include
+    print(f"#define FLASH_DISCRIM {json_flags['flash-discriminator']}",
+          file=open("include/flashdiscrim.h", "w"))