Add CMake build directory patterns to .gitignore #1775

1. 
   hebasto commented at 10:27 am on November 18, 2025: member

   Whenever I work on changes that require comparison, such as benchmarking, I end up with two or more build directories that provide different binary variants simultaneously. Adding these build directories to .gitignore makes the workflow a bit easier.

   Additionally, a trivial refactoring is included to reduce the code.

2. in .gitignore:56 in 90b3339481 outdated

   67 ### CMake
   68 /CMakeUserPresets.json
   69-# Default CMake build directory.
   70-/build
   71+# CMake build directories.
   72+/*build*
   

   ---

   ---

   

   hebasto commented at 10:28 am on November 18, 2025:

   The same pattern is used in Bitcoin Core.
3. 
   real-or-random commented at 10:36 am on November 18, 2025: contributor

   Concept ACK

   We could also get rid of build-aux entirely by moving the contents of the only file into configure.ac. I think that would be nice. build-aux can be confusing to people familiar only with CMake, and it hinders tab-completion with CMake dirs etc… What do you think?

4. real-or-random added the label build on Nov 18, 2025
5. real-or-random added the label tweak/refactor on Nov 18, 2025
6. 
   hebasto commented at 1:28 pm on November 18, 2025: member

   We could also get rid of build-aux entirely by moving the contents of the only file into configure.ac. I think that would be nice.

   I think the main purpose of:https://github.com/bitcoin-core/secp256k1/blob/b6c2a3cd7752085d46434921238401766c964c01/configure.ac#L22 is to keep the top level of the repo uncluttered. Without it, it would end up filled as follows:

   0$ ./autogen.sh | grep -v libtoolize
   1configure.ac:38: installing './ar-lib'
   2configure.ac:36: installing './compile'
   3configure.ac:23: installing './config.guess'
   4configure.ac:23: installing './config.sub'
   5configure.ac:26: installing './install-sh'
   6configure.ac:26: installing './missing'
   7Makefile.am: installing './depcomp'
   8parallel-tests: installing './test-driver'
   

   build-aux can be confusing to people familiar only with CMake, and it hinders tab-completion with CMake dirs etc… What do you think?

   The build-aux directory could be renamed. Perhaps to something like autotools-aux?

7. 
   real-or-random commented at 7:43 pm on November 19, 2025: contributor

   Oh sure! Even I forgot the main purpose of the directory.

   The build-aux directory could be renamed. Perhaps to something like autotools-aux?

   I like that suggestion.

8. autotools: Rename `build-aux` to `autotools-aux`

   This change improves separation from CMake build directories, which
   typically use the "build" prefix.
   
   Additionally, corresponding `.gitignore` entries have been refactored.

   7eb86bdb01
9. Add CMake build directory patterns to `.gitignore` 748c0fdd67
10. hebasto force-pushed on Nov 20, 2025
11. 
    hebasto commented at 12:44 pm on November 20, 2025: member

    The build-aux directory could be renamed. Perhaps to something like autotools-aux?

    I like that suggestion.

    Thanks! Done.

Contributors
hebasto real-or-random

Labels
build tweak/refactor