[libc][docs] Add net/if.h documentation by referring to POSIX standards

[StarOne01]

This pull request introduces the following changes to the project with reference to issue ( #122006 ):

1. Documentation Update:

   • Added a new YAML file if.yaml under net to document network interface functions and macros.
   • The if.yaml file includes the following functions and macros:
     • Functions:
       • if_freenameindex
       • if_indextoname
       • if_nameindex
       • if_nametoindex
     • Macros:
       • IF_NAMESIZE

2. CMake Configuration Update:

   • Updated the CMakeLists.txt file to create the necessary directory for the net headers.
   • Included the net/if documentation in the Sphinx build configuration.

3. Index Update:

   • Updated the index.rst file to include a reference to the newly added net/if documentation.

Purpose:

• This pull request adds documentation for network interface functions and macros, ensuring they are included in the project's documentation.
• Updates the CMake configuration to support the new documentation.

Testing:

• Verified that the new YAML file is correctly referenced in the index.rst.
• Ensured that the documentation builds without errors and includes the new network interface documentation.

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[llvmbot]

@llvm/pr-subscribers-libc

Author: Prashanth (StarOne01)

Changes

This pull request introduces the following changes to the project:

1. Documentation Update:

   • Added a new YAML file if.yaml under net to document network interface functions and macros.
   • The if.yaml file includes the following functions and macros:
     • Functions:
       • if_freenameindex
       • if_indextoname
       • if_nameindex
       • if_nametoindex
     • Macros:
       • IF_NAMESIZE

2. CMake Configuration Update:

   • Updated the CMakeLists.txt file to create the necessary directory for the net headers.
   • Included the net/if documentation in the Sphinx build configuration.

3. Index Update:

   • Updated the index.rst file to include a reference to the newly added net/if documentation.

Purpose:

• This pull request adds documentation for network interface functions and macros, ensuring they are included in the project's documentation.
• Updates the CMake configuration to support the new documentation.

Testing:

• Verified that the new YAML file is correctly referenced in the index.rst.
• Ensured that the documentation builds without errors and includes the new network interface documentation.

---

Full diff: https://github.com/llvm/llvm-project/pull/122406.diff

3 Files Affected:

• (modified) libc/docs/CMakeLists.txt (+2)
• (modified) libc/docs/headers/index.rst (+1)
• (added) libc/utils/docgen/net/if.yaml (+13)

diff --git a/libc/docs/CMakeLists.txt b/libc/docs/CMakeLists.txt
index 5a3f8275bb932e..a21d8e563626c5 100644
--- a/libc/docs/CMakeLists.txt
+++ b/libc/docs/CMakeLists.txt
@@ -19,6 +19,7 @@ if (SPHINX_FOUND)
     file(MAKE_DIRECTORY
       "${CMAKE_CURRENT_BINARY_DIR}/headers/arpa/"
       "${CMAKE_CURRENT_BINARY_DIR}/headers/sys/"
+      "${CMAKE_CURRENT_BINARY_DIR}/headers/net/"
     )
 
     # Change sphinx to build from $build_dir/libc/docs/ rather than
@@ -40,6 +41,7 @@ if (SPHINX_FOUND)
       float
       inttypes
       locale
+      net/if
       setjmp
       signal
       stdbit
diff --git a/libc/docs/headers/index.rst b/libc/docs/headers/index.rst
index 07ab6dd9b26742..b78ae86e968d9a 100644
--- a/libc/docs/headers/index.rst
+++ b/libc/docs/headers/index.rst
@@ -14,6 +14,7 @@ Implementation Status
    inttypes
    locale
    math/index.rst
+   net/if
    search
    setjmp
    signal
diff --git a/libc/utils/docgen/net/if.yaml b/libc/utils/docgen/net/if.yaml
new file mode 100644
index 00000000000000..085d27b2bb94fa
--- /dev/null
+++ b/libc/utils/docgen/net/if.yaml
@@ -0,0 +1,13 @@
+functions:
+  if_freenameindex:
+    in-latest-posix: ''
+  if_indextoname:
+    in-latest-posix: ''
+  if_nameindex:
+    in-latest-posix: ''
+  if_nametoindex:
+    in-latest-posix: ''
+
+macros:
+  IF_NAMESIZE:
+    in-latest-posix: ''
\ No newline at end of file