build: support static build #34728

(cherry picked from commit e91224bfaa)

BUILD.md

@@ -259,6 +259,29 @@ cmake --build build
     - Using `ninja` is strongly recommended.
 4. If treesitter parsers are not bundled, they need to be available in a `parser/` runtime directory (e.g. `/usr/share/nvim/runtime/parser/`).
 
+### How to build static binary (on Linux)
+
+1. Use a linux distribution which uses musl C. We will use Alpine Linux but any distro with musl should work. (glibc does not support static linking)
+2. Run make passing the `STATIC_BUILD` variable: `make CMAKE_EXTRA_FLAGS="-DSTATIC_BUILD=1"`
+
+In case you are not using Alpine Linux you can use a container to do the build the binary:
+
+```bash
+podman run \
+  --rm \
+  -it \
+  -v "$PWD:/workdir" \
+  -w /workdir \
+  alpine:latest \
+  bash -c 'apk add build-base cmake coreutils curl gettext-tiny-dev && make CMAKE_EXTRA_FLAGS="-DSTATIC_BUILD=1"'
+```
+
+The resulting binary in `build/bin/nvim` will have all the dependencies statically linked:
+
+```
+build/bin/nvim: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, BuildID[sha1]=b93fa8e678d508ac0a76a2e3da20b119105f1b2d, with debug_info, not stripped
+```
+
 #### Debian 10 (Buster) example:
 
 ```sh

src/nvim/CMakeLists.txt

@@ -742,7 +742,11 @@ endif()
 
 target_sources(nlua0 PUBLIC ${NLUA0_SOURCES})
 
+if(STATIC_BUILD)
+  target_link_options(nvim_bin PRIVATE -static-libgcc -static-libstdc++ -static)
+endif()
 target_link_libraries(nvim_bin PRIVATE main_lib PUBLIC libuv)
+
 install_helper(TARGETS nvim_bin)
 if(MSVC)
   install(FILES $<TARGET_PDB_FILE:nvim_bin> DESTINATION ${CMAKE_INSTALL_BINDIR} OPTIONAL)