Espressif has switched from the binutils-esp32ulp repo (the originalfork of binutils to support their microcontrollers) to their newrepo binutils-gdb. (seeespressif/esp-idf@a9bd454)The ESP-IDF also uses the esp32ulp assembler/linker from the newrepo now. The main difference is that this is now the officiallymaintained implementation. The other difference is that there are nownot different binaries for each esp32 variant, but one set of binaries.To select which esp32 variant to target, the esp32ulp-elf-as binarynow accepts the --mcpu argument, for example --mcpu=esp32s2. Thedefault is still the original esp32, so omitting the argument meansone effected selected --mcpu=esp32.Note: Because Espressif provides pre-built binaries we are no longerbuilding esp32ulp, but simply downloading the binaries and usingthose.

The examples from the testsuite are the same as in the previousbinutils-esp32ulp repo from Espressif. But since the old repowill no longer be maintained, we switch to the new one.Currently all development happens on the esp32ulp-elf-2.35 branchand master does not (yet?) contain any files related to theEspressif-adapted assembler/linker. So we use this branch for now.Given that the branch name includes what appears to be a versionnumber, it could mean Espressif might switch to a different branchdown the line. We should pay attention to this and can then chooseto switch to that branch too.

When using binutils-gdb (esp32ulp) to generate the "reference binary",which we compare against, pass --mcpu=esp32 to select the originalESP32 variant. While this is the default target of esp32-ulp-as,adding this argument makes the choice explicit and shows how to selecta variant, for when we add support the ESP32-S2 or ESP32-S3 (bothuse --mcpu=esp32s2 because their ULPs have the same binary format).