hard-coded bin path and NixOS

When I try to do a manual source install of some software on NixOS 15.09, I get (sh -x is to get an exec log):

[nix-shell:/tmp/nix-shell-es/EventStore-oss-v3.5.0-src]$ sh -x scripts/build-js1/build-js1-linux.sh werror=no

...
+ CXXFLAGS=-fPIC
+ make x64.release werror=no
PYTHONPATH="/tmp/nix-shell-es/EventStore-oss-v3.5.0-src/scripts/build-js1/v8/tools/generate_shim_headers:" 
GYP_GENERATORS=make 
build/gyp/gyp --generator-output="out" build/all.gyp 
              -Ibuild/standalone.gypi --depth=. 
              -Dv8_target_arch=x64 
              -Dv8_optimized_debug=0 
              -S.x64.release  -Dv8_enable_backtrace=1 -Dwerror='' -Darm_fpu=default -Darm_float_abi=default
/bin/sh: build/gyp/gyp: /bin/bash: bad interpreter: No such file or directory
Makefile:389: recipe for target 'out/Makefile.x64.release' failed
make: *** [out/Makefile.x64.release] Error 126

And indeed there is no bash program in /bin/

[nix-shell:/tmp/nix-shell-es/EventStore-oss-v3.5.0-src]$ ls -la /bin/
total 12
drwxr-xr-x  2 root root 4096 Feb 24 12:25 .
drwxr-xr-x 18 root root 4096 Feb 24 12:16 ..
lrwxrwxrwx  1 root root   63 Feb 24 12:25 sh -> /nix/store/l80ddf18bbig2icv6cmgjfws9a2vm3jj-bash-4.3-p42/bin/sh

However when I inspect the script I dont see any mention of it so it must be some subprogram looking for it. As an aside, I imagine that’s probably why the script wisely starts with #!/usr/bin/env bash and not the direct location of bash.

Anyone knows a blessed way to deal with this ?

Answer

one has to run patchShebangs ./scripts/build-js1/build-js1-linux.sh on files coming from source when they are not in the store and we want to execute them.