This change improves build consistency across external projects integrated
through CMake by ensuring that compiler flags defined in configuration files
are passed correctly to the toolchain. It covers the majority of use cases,
as external projects are typically also CMake-based. For projects that use
a custom build system, users will still need to specify the required flags
manually.
Currently, the toolchain CMake files use the remove_duplicated_flags
function from utilities.cmake. The cmakev2 implementation also includes
this function for backward compatibility. Move the
remove_duplicated_flags function to a separate file,
deduplicate_flags.cmake, so it can be shared between cmakev1 and
cmakev2.
Signed-off-by: Frantisek Hrbata <frantisek.hrbata@espressif.com>
The toolchain files are using the remove_duplicated_flags function from
utilities.cmake. However, we want to avoid mixing utilities from cmakev1
and cmakev2. Use `IDF_BUILD_VER_TAG` to include utilities from the
currently used build system version.
Signed-off-by: Frantisek Hrbata <frantisek.hrbata@espressif.com>
Defining CMake variables from the command-line or from another CMake project,
such as `-DCMAKE_C_FLAGS= -DCMAKE_CXX_FLAGS=`, caused a link failure as ESP
CMake was unable to set its proper compilation flags.
Additional CMake compiler flags can now be provided by another project.
* Closes https://github.com/espressif/esp-idf/issues/7507
-nostdlib was removed in 9a2af7a and then accidentally added
in 1c2cc54.
The issue manifested itself as a failure to link some symbols from
libgcc, even though libgcc should implicitly appear at the end of the
linker command line when -nostdlib is not given.
