add testcase for LTO with picolibc module

[benediktibk]

Add a testcase which builds with LTO and the picolibc module.

[benediktibk]

Testcase for #81674

[benediktibk]

With the fix in #83132 of @keith-packard these tests now run successfully. There is only one small caveat: We pass -flto and -fno-lto at the same time, but it looks like later flags override the previous ones: https://stackoverflow.com/questions/15909788/how-does-gcc-behave-if-passed-conflicting-compiler-flags

.../zephyr-sdk-0.16.1/arm-zephyr-eabi/bin/arm-zephyr-eabi-gcc
-DCORE_CM7
-DHSE_VALUE=8000000
-DKERNEL
-DK_HEAP_MEM_POOL_SIZE=0
-DSTM32F746xx
-DUSE_FULL_LL_DRIVER
-DUSE_HAL_DRIVER
-D__LINUX_ERRNO_EXTENSIONS__
-D__PROGRAM_START
-D__ZEPHYR__=1
-I.../build/twister/nucleo_f746zg_stm32f746xx/tests/misc/test_build/buildsystem.lto.picolibc_module/zephyr/include/generated/zephyr
-I.../zephyr/include
-I.../build/twister/nucleo_f746zg_stm32f746xx/tests/misc/test_build/buildsystem.lto.picolibc_module/zephyr/include/generated
-I.../zephyr/soc/st/stm32
-I.../zephyr/soc/st/stm32/common/.
-I.../zephyr/drivers
-I.../zephyr/soc/st/stm32/stm32f7x/.
-I.../modules/hal/cmsis/CMSIS/Core/Include
-I.../zephyr/modules/cmsis/.
-I.../modules/hal/stm32/stm32cube/stm32f7xx/soc
-I.../modules/hal/stm32/stm32cube/stm32f7xx/drivers/include
-I.../modules/hal/stm32/stm32cube/common_ll/include
-isystem
.../zephyr/lib/libc/common/include
-isystem
.../build/twister/nucleo_f746zg_stm32f746xx/tests/misc/test_build/buildsystem.lto.picolibc_module/modules/picolibc/picolibc/include
-isystem
.../zephyr-sdk-0.16.1/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/include
-isystem
.../zephyr-sdk-0.16.1/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/include-fixed
-Wshadow
-fno-strict-aliasing
-Werror
-Os
-flto=auto
-imacros
.../build/twister/nucleo_f746zg_stm32f746xx/tests/misc/test_build/buildsystem.lto.picolibc_module/zephyr/include/generated/zephyr/autoconf.h
-fno-printf-return-value
-fno-common
-g
-gdwarf-4
-fdiagnostics-color=always
-mcpu=cortex-m7
-mthumb
-mabi=aapcs
-mfp16-format=ieee
-mtp=soft
--sysroot=.../zephyr-sdk-0.16.1/arm-zephyr-eabi/arm-zephyr-eabi
-imacros
.../zephyr/include/zephyr/toolchain/zephyr_stdint.h
-Wall
-Wformat
-Wformat-security
-Wno-format-zero-length
-Wdouble-promotion
-Wno-pointer-sign
-Wpointer-arith
-Wexpansion-to-defined
-Wno-unused-but-set-variable
-Werror=implicit-int
-fno-pic
-fno-pie
-fno-asynchronous-unwind-tables
-ftls-model=local-exec
-fno-reorder-functions
--param=min-pagesize=0
-fno-defer-pop
-fmacro-prefix-map=.../zephyr/tests/misc/test_build=CMAKE_SOURCE_DIR
-fmacro-prefix-map=.../zephyr=ZEPHYR_BASE
-fmacro-prefix-map=...=WEST_TOPDIR
-ffunction-sections
-fdata-sections
-std=c99
-nostdinc
-fno-lto
-MD
-MT
zephyr/lib/libc/picolibc/CMakeFiles/lib__libc__picolibc.dir/stdio.c.obj
-MF
zephyr/lib/libc/picolibc/CMakeFiles/lib__libc__picolibc.dir/stdio.c.obj.d
-o
zephyr/lib/libc/picolibc/CMakeFiles/lib__libc__picolibc.dir/stdio.c.obj
-c
.../zephyr/lib/libc/picolibc/stdio.c

[aescolar]

+1