root@c5799e87a84e:/src# emconfigure ./configure LDFLAGS='-sEXPORT_ES6=1'
configure: ./configure LDFLAGS=-sEXPORT_ES6=1
checking for gcc... /emsdk/upstream/emscripten/emcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether the compiler supports GNU C... yes
checking whether /emsdk/upstream/emscripten/emcc accepts -g... yes
checking for /emsdk/upstream/emscripten/emcc option to enable C11 features... none needed
configure: creating ./config.status
root@c5799e87a84e:/src# emconfigure ./configure
configure: ./configure
checking for gcc... /emsdk/upstream/emscripten/emcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... configure: error: in `/src':
configure: error: cannot run C compiled programs.
If you meant to cross compile, use `--host'.
See `config.log' for more details
emconfigure: error: './configure' failed (returned 77)