Add fxdiv

[Alex-PLACET]

Added recipes/recipes_emscripten/[package-name]/recipe.yaml with proper structure:

• context section with version (and optionally name)
• package section with name and version using Jinja2 templates
• source section with:
  • Source URL is valid and points to archive file (.tar.gz, .tar.bz2, .tar.xz, .tgz, or .zip)
  • Source URL contains ${{ version }} template for version updates
  • SHA256 hash is correct (verified with curl -sL <url> | sha256sum)
  • Patches (if any) are included in [package-name]/patches/ directory
• build section with appropriate script/method
  • Python packages: ${PYTHON} -m pip install . ${PIP_ARGS}
  • R packages: $R CMD INSTALL $R_ARGS .
  • C++ packages: Uses emcmake/emmake or emconfigure/emmake
  • Rust packages: Uses rust-nightly and maturin or appropriate Rust build tool
  • Build number is 0
  • If the script is longer than 3 lines, a build.sh is included
• requirements section (build, host, run as needed)
• tests section
  • Python packages: test_import_[package].py file created and referenced
  • C++ packages: Test executable or package_contents test
  • R packages: Package contents test
• about section with license, homepage, summary

PR Formatting

• PR title follows format: Add [package-name] or Update [package-name] to [version]
• PR description includes:
  • Version being added/updated
  • Any special build considerations or patches applied

Package Details

• Package Name: fxdiv
• Version: 63058eff77e11aa15bf531df5dd34395ec3017c8

[IsabelParedes]

Since this package is a single header file, we should make it noarch: generic

Similar to https://github.com/emscripten-forge/recipes/blob/main/recipes/recipes_emscripten/clang-resource-headers/recipe.yaml