stm32cube: get rid of the HAL Legacy definitions header

stm32cube/CMakeLists.txt

@@ -139,3 +139,24 @@ endif()
 
 # Add the series-agnostic LL headers to include directories
 zephyr_include_directories(common_ll/include)
+
+# Add placeholder for STM32Cube HAL Legacy definitions header
+#
+# Each serie's STM32Cube package originally contains a header
+# provided for compatibility and filled with "old names" of
+# various Cube definitions. These are not used from Zephyr
+# as drivers should always be using the up-to-date Cube API
+# and, more importantly, some of these "legacy" definitions
+# clash with macros provided by Zephyr which breaks build!
+#
+# Sadly, the header can't be simply discarded when STM32Cube
+# packages are added to this repository as it is included
+# unconditionally by "stm32XXXxx_hal_def.h", a header which
+# provides definitions we do need. To avoid the maintenance
+# burden of patching every STM32Cube package to remove the
+# the offending `#include "Legacy/stm32_hal_legacy.h"`, we
+# instead do discard the Legacy header but add a carefully
+# crafted directory to the include path such that, when the
+# offending `#include` line is reached, it ends up including
+# an empty header file and everything works out :)
+zephyr_include_directories(cube_legacy_placeholder)

stm32cube/cube_legacy_placeholder/Legacy/stm32_hal_legacy.h

@@ -0,0 +1 @@
+/* Dummy replacement for HAL Legacy definitions header (c.f., CMakeLists.txt) */

stm32cube/stm32c0xx/README

@@ -40,8 +40,4 @@ Patch List:
     -Added stm32cube/stm32c0xx/drivers/include/stm32_assert.h
     -Removed unused stm32cube/stm32c0xx/drivers/include/stm32_assert_template.h
 
-   *Fix to remove PAGESIZE definition which conflicts with POSIX
-    Impacted files:
-     drivers/include/Legacy/stm32_hal_legacy.h
-
    See release_note.html from STM32Cube

stm32cube/stm32f0xx/README

@@ -47,8 +47,4 @@ Patch List:
     -Added stm32cube/stm32f0xx/drivers/include/stm32_assert.h
     -Removed unused stm32cube/stm32f0xx/drivers/include/stm32_assert_template.h
 
-   *Fix to remove PAGESIZE definition which conflicts with POSIX
-    Impacted files:
-     drivers/include/Legacy/stm32_hal_legacy.h
-
    See release_note.html from STM32Cube

stm32cube/stm32f1xx/README

@@ -52,8 +52,4 @@ Patch List:
     -Added stm32cube/stm32f1xx/drivers/include/stm32_assert.h
     -Removed unused stm32cube/stm32f1xx/drivers/include/stm32_assert_template.h
 
-   *Fix to remove PAGESIZE definition which conflicts with POSIX
-    Impacted files:
-     drivers/include/Legacy/stm32_hal_legacy.h
-
    See release_note.html from STM32Cube