Allow building as a static -fPIC library

src/nvim/CMakeLists.txt

@@ -208,6 +208,14 @@ if(SANITIZE)
   set_property(TARGET nvim APPEND_STRING PROPERTY LINK_FLAGS "-fsanitize=address -fsanitize=undefined ")
 endif()
 
+add_library(libnvim STATIC EXCLUDE_FROM_ALL ${NEOVIM_GENERATED_SOURCES}
+  ${NEOVIM_SOURCES} ${NEOVIM_HEADERS})
+target_link_libraries(libnvim ${NVIM_LINK_LIBRARIES})
+set_target_properties(libnvim PROPERTIES
+  POSITION_INDEPENDENT_CODE ON
+  OUTPUT_NAME nvim)
+set_property(TARGET libnvim APPEND_STRING PROPERTY COMPILE_FLAGS " -DMAKE_LIB ")
+
 add_library(nvim-test MODULE EXCLUDE_FROM_ALL ${NEOVIM_GENERATED_SOURCES}
     ${NEOVIM_SOURCES} ${NEOVIM_HEADERS})
 target_link_libraries(nvim-test ${NVIM_LINK_LIBRARIES})

src/nvim/main.c

@@ -194,7 +194,11 @@ void early_init(void)
 }
 
 #ifndef NO_VIM_MAIN     /* skip this for unittests */
+#ifdef MAKE_LIB
+int nvim_main(int argc, char **argv)
+#else
 int main(int argc, char **argv)
+#endif
 {
   char_u      *fname = NULL;            /* file name from command line */
   mparm_T params;                       /* various parameters passed between