$ opam install srt
The following actions will be performed:
  ∗ install integers   0.3.0  [required by ctypes]
  ∗ install ctypes     0.17.1 [required by srt]
  ∗ install sys-socket 1.0.0  [required by srt]
  ∗ install srt        0.1.0
===== ∗ 4 =====
Do you want to continue? [Y/n] y
<><> Gathering sources ><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
[integers.0.3.0] downloaded from cache at https://opam.ocaml.org/cache
[srt.0.1.0] downloaded from cache at https://opam.ocaml.org/cache
[sys-socket.1.0.0] downloaded from cache at https://opam.ocaml.org/cache
[ctypes.0.17.1] downloaded from cache at https://opam.ocaml.org/cache
<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
∗ installed integers.0.3.0
∗ installed ctypes.0.17.1
∗ installed sys-socket.1.0.0
[ERROR] The compilation of srt failed at
        "/home/tristan/.opam/opam-init/hooks/sandbox.sh build dune build -p srt
        -j 1".
#=== ERROR while compiling srt.0.1.0 ==========================================#
# context     2.0.6 | linux/x86_64 | ocaml-base-compiler.4.08.0 | https://opam.ocaml.org#d67e70b4
# path        ~/.opam/4.08.0/.opam-switch/build/srt.0.1.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p srt -j 1
# exit-code   1
# env-file    ~/.opam/log/srt-14638-b1238c.env
# output-file ~/.opam/log/srt-14638-b1238c.out
### output ###
# srt_generated_stubs.c:29:36: warning: implicit declaration of function 'pthread_getspecific' [-Wimplicit-function-declaration]
# [...]
# srt_generated_stubs.c:30:5: warning: implicit declaration of function 'pthread_setspecific' [-Wimplicit-function-declaration]
#    30 |     pthread_setspecific(ocaml_c_thread_key,(void*)&initialized);
#       |     ^~~~~~~~~~~~~~~~~~~
# srt_generated_stubs.c: In function 'ocaml_srt_7_srt_socket':
# srt_generated_stubs.c:147:4: warning: 'srt_socket' is deprecated [-Wdeprecated-declarations]
#   147 |    int x44 = srt_socket(x35, x38, x41);
#       |    ^~~
# In file included from srt_generated_stubs.c:2:
# /usr/local/include/srt/srt.h:725:41: note: declared here
#   725 | SRT_ATR_DEPRECATED_PX SRT_API SRTSOCKET srt_socket(int, int, int) SRT_ATR_DEPRECATED;
#       |                                         ^~~~~~~~~~
<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
┌─ The following actions failed
│ λ build srt 0.1.0
└─
┌─ The following changes have been performed
│ ∗ install ctypes     0.17.1
│ ∗ install integers   0.3.0
│ ∗ install sys-socket 1.0.0
└─
The packages you requested declare the following system dependencies. Please
make sure they are installed before retrying:
    libsrt-dev
The former state can be restored with:
    opam switch import
"/home/tristan/.opam/4.08.0/.opam-switch/backup/state-20200406092429.export"