cmake: Some improvements using PROJECT_IS_TOP_LEVEL variable #1284

1. 
   hebasto commented at 10:29 pm on April 20, 2023: member

   This PR:

   1. Emulates PROJECT_IS_TOP_LEVEL variable for CMake versions where it is not available.
   2. Makes the SECP256K1_INSTALL option dependent on PROJECT_IS_TOP_LEVEL (a follow up of #1263).
   3. Makes integration of this project as a subtree easier. A top project can #include <secp256k1.h> with no additional target_include_directories() commands. For example, see https://github.com/hebasto/secp256k1-CMake-example/tree/subtree.
2. cmake: Emulate `PROJECT_IS_TOP_LEVEL` for CMake<3.21 162608cc98
3. hebasto cross-referenced this on Apr 20, 2023 from issue cmake: Make installation optional by CyberTailor
4. in CMakeLists.txt:48 in b9112aa61b outdated

   45   set(BUILD_SHARED_LIBS OFF)
   46 endif()
   47 
   48-option(SECP256K1_INSTALL "Enable installation" ON)
   49+include(CMakeDependentOption)
   50+cmake_dependent_option(SECP256K1_INSTALL "Enable installation." ON "PROJECT_IS_TOP_LEVEL" OFF)
   

   ---

   ---

   

   real-or-random commented at 8:22 am on April 21, 2023:

   Does it really make sense to forbid installation if used as a subproject? I think we could let the user decide here.

   ---

   

   hebasto commented at 11:07 am on April 21, 2023:

   Thanks! Updated.
5. 
   real-or-random commented at 8:22 am on April 21, 2023: contributor

   Concept ACK
6. cmake: Make `SECP256K1_INSTALL` default depend on `PROJECT_IS_TOP_LEVEL`

   Also full stops have been added to the option help texts for consistency
   in cmake-gui.

   5431b9decd
7. hebasto force-pushed on Apr 21, 2023
8. 
   hebasto commented at 11:06 am on April 21, 2023: member

   Updated b9112aa61b9a0cd9e6f790b920568b85be1d5b8a -> 009faea5c6f48b0d7b7c2bf87caf44621b6c6b21 (pr1284.01 -> pr1284.02, diff):

   • addressed @real-or-random’s comment
9. real-or-random approved
10. 
    real-or-random commented at 11:24 am on April 21, 2023: contributor

    utACK 009faea5c6f48b0d7b7c2bf87caf44621b6c6b21
11. real-or-random approved
12. 
    real-or-random commented at 3:44 pm on April 26, 2023: contributor

    [edited: nevermind, I acked the wrong PR…]
13. real-or-random cross-referenced this on Apr 27, 2023 from issue build: Meta-issue for follow-ups to initial CMake merge (#1113) by hebasto
14. in src/CMakeLists.txt:36 in 009faea5c6 outdated

    30@@ -31,7 +31,8 @@ endif()
    31 get_target_property(use_pic secp256k1 POSITION_INDEPENDENT_CODE)
    32 set_target_properties(secp256k1_precomputed PROPERTIES POSITION_INDEPENDENT_CODE ${use_pic})
    33 
    34-target_include_directories(secp256k1 PUBLIC
    35+target_include_directories(secp256k1 INTERFACE
    36+  $<BUILD_INTERFACE:$<$<NOT:$<BOOL:${PROJECT_IS_TOP_LEVEL}>>:${PROJECT_SOURCE_DIR}/include>>
    

    ---

    ---

    

    theuni commented at 2:12 pm on April 27, 2023:

    Can we get a comment? Something like: “Add the include path for parent projects so that they don’t have to manually add it.”
15. 
    theuni commented at 2:12 pm on April 27, 2023: contributor

    ACK modulo comment request.
16. cmake: Include `include` directory for subtree builds 71f746c057
17. hebasto force-pushed on Apr 27, 2023
18. 
    theuni commented at 2:17 pm on April 27, 2023: contributor

    Hah, that was fast!

    utACK 71f746c057a66d5ae0dfdb5d439bc49592c0d16e.

19. real-or-random merged this on Apr 27, 2023
20. real-or-random closed this on Apr 27, 2023

    ---

21. hebasto deleted the branch on Apr 28, 2023
22. sipa referenced this in commit b4eb644b6c on May 12, 2023
23. hebasto referenced this in commit 49c52ea2b1 on May 13, 2023
24. vmta referenced this in commit e1120c94a1 on Jun 4, 2023
25. sipa referenced this in commit 901336eee7 on Jun 21, 2023
26. vmta referenced this in commit 8f03457eed on Jul 1, 2023
27. jonasnick cross-referenced this on Jul 24, 2023 from issue Upstream PRs 1268, 1276, 1267, 1265, 1230, 1279, 1273, 1263, 1231, 1285, 1283, 1205, 1286, 1275, 1234, 1239, 1240, 1284, 1277, 1289, 1270, 1296, 1301, 1299, 1066, 1300, 1292, 1305, 1303, 1133, 1306, 1207, 1304, 1307, 1311, 1309, 1312 by jonasnick

Contributors
hebasto real-or-random theuni